Hard (re)starting list-side engine (ballasted AR240, wake surfing)

[swatski]

If water can make it into the cylinder while towing it is possible. You may not get hydro lock but if the water is making its way so far up the exhaust and its hitting areas that are obviously hot it could be creating steam vapors that are throwing off the combustion mixture. The only way to rule this out is to pull a plug and look for moisture. Or the manifold cooling lines in relation to the water level could be the entry point




A "good foot plus" is inaccurate confirmed measurements from an AR230 the center of the impeller shaft is 14'' below the lower swim deck.The highest point of the cooling lines is 10'' above the center of the shaft so that if the water is level with the swim deck its only 4'' above the highest point in the cooling lines . Different models but they are most likely close take some measurements with it sitting on the trailer you will be surprised

If the rear swim platform is 4'' under water its almost in line with the highest cooling line the variables are the boat is most likely sitting lower in the back and not level but with the large wave following the boat will make the front end drop and a rocking motion could allow water to works it way up

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If the boat was completely balanced and pushed straight down at some point the water level will find its way into the cylinder I think this point is with the swim deck 4'' below the water line. Water will equalize and with these boats loaded with ballast I think your very close to that fine line

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Someone needs to pull the plug it would be great to eliminate this possibility and may even be hard to determine but take a look

I understand the idea, but that is just not the case. The water from outside is not reaching the cylinders in any of those ballast scenarios. It can happen when it is pushed through the exhaust at speed or if the intakes start taking it.

When ballasted, the boat sits w/ nose up, so these measurements are completely off as far as the water plane, it is a foot plus in my boat as far as exhaust manifold parts etc.
In my OEM exhaust the water will not get past the water box, if any would flow (above) and through the resonator at all, unless the boat was sinking...
The water box is always cold or cool, it never gets hot. It is sitting in the bilge not the engine compartment, which is smart. Everything gets hot in the engine compartment.

Of course some water vapor/fog will be created in the exhaust but that will not lock the engine and will be expelled with the first crank.

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[Cambo]

it is a foot plus in my boat as far as exhaust manifold parts etc.

When the boat is on plane this may be the case but when floating with no power your jet nozzles are submerged under water and the impeller shaft is not much lower than the highest cooling line. Post the measurements of the center of your jet nozzle to the lower swim deck then the measurement of the center of the impeller shaft to the top bolts of the manifold in the engine bay at the most its about 5 difference''

Yes the nose is up but no way is it a foot plus to the exhaust manifold while not under power. This is not my boat but it looks like the water line could almost be up to the second level . How big is the wave that washes onto the back deck if you come to an abrupt stop ? Does it ever make it close to spill over coming into the seating area? Do you notice water in the bilge after a heavy day of surfing from the wave washing up and spilling into the engine compartment ?

 

[Cambo]

Post up some measurements the only variable is how much the boat is pitched . That could be calculated with a 2 foot level on the water if the nose was up 2 feet more than being level that is a fairly steep pitch that would only get you 3'' over 3 feet or 2'' over 2 feet I'm not sure of the distance from the jet nozzle to the highest cooling line on the motor

Any surfers have a 2 foot level and tape measure see how far the motor is from being level over a 2 foot run

 

[swatski]

Post up some measurements the only variable is how much the boat is pitched . That could be calculated with a 2 foot level on the water if the nose was up 2 feet more than being level that is a fairly steep pitch that would only get you 3'' over 3 feet or 2'' over 2 feet I'm not sure of the distance from the jet nozzle to the highest cooling line on the motor

Any surfers have a 2 foot level and tape measure see how far the motor is form being level over a 2 foot run

View attachment 79051

Yes, you are making very good points. I get it, too. You maybe correct about the distances, albeit the "boat pitch" would go the other way. I have not taken the time to measure the distance between those points myself, so no reason to doubt your measurements.

However...

the exhaust in these boats is not a simple pipe but rather a deliberately tortuous path meant to slow the water intrusion - characteristic of all boats with rear exhaust outlets - with an entry valve and a system of two large "siphon" structures/reservoirs - first is the resonator box, the other is water box. Water box is actually called "water lock" in part fiches I believe, for a reason. In addition, the system was designed so there is significant amount of back-pressure to overcome - to move the water up /through this exhaust system.

There have been many examples of boats with swamped engine compartments due to water intrusion where the engines started right away - as long as the water level did not reach the air intakes.

I think it is extremely unlikely that the symptoms we are describing in this thread result from a hydrolock of any kind. I have come to think that the exhaust part of the equation here, including building the back pressure/steam/moisture/what-not may be a part of the issue, but it is not the critical part.

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[Cambo]

"boat pitch" would go the other way

the green line is designating the pitch of the boat that the Bow or "nose" would be higher in relation to the jet nozzle

The water lock on these boats is week for its description its is mainly designed to muffle how loud these motors are if anyone has heard a jets ski that has had the water box removed you will know what I mean. look up a water lock design the pipe will rise very high to keep water out due to the rocking motion from waves that could allow water to works its way back up.


There is no water lock on the water cooling line it flows free and at some point the water could find its way in



Hydro lock would destroy the motor that has not been reported these motors can easily operate with a small amount of water splashing into the cylinders but they don't run correctly and I think that is the root cause of this issue.

For the fan mod that seems to be working could it be that you are more in tune with the motors being hot and slowing down without abruptly stopping preventing the rocking motion of the boat. I think its this rocking motion in combination with the ballast allowing the water to works its way further up the system and creating some type of steam or drips of water to throw off the combustion

The boats that have flooded the engine compartments the difference between the highest water point and the intakes are a few inches apart . Yes they were very close to ingesting water some did and destroyed the motors.

If someone can pull a plug when the issue pops up it may shed some light. Its a lot easier than installing fans

 

[swatski]

I appreciate your suggestions but must admit I'm a bit confused.

First, the exhaust is quite impervious to water intrusion and one can not ignore the back pressure aspect of this exhaust system. This is an extremely robust engine designed to run in small boats and jet skis - water intrusion inside the cylinders of those engines due to ballast/list/rocking motion of those boats is completely improbable.

The hard starts clearly correlate with engine heat/heat-soak/heat-sink.

I think the back pressure hypothesis is valid and I was convinced that is THE issue. The fact that moving the boat up on plane with one engine running - either by using tabs in my case, or by forcing a tight turn as @0627Devildog reported - certainly supports that.

However...

running hard w/ one engine also forces cold air flow (as that engine moves more than 10x the mass of air of what the blower fan can do). Given the blower alone appears sufficient to alleviate the problem, a common factor could be air flow.

these motors can easily operate with a small amount of water splashing into the cylinders

???

For the fan mod that seems to be working could it be that you are more in tune with the motors being hot and slowing down without abruptly stopping preventing the rocking motion of the boat. I think its this rocking motion in combination with the ballast allowing the water to works its way further up the system and creating some type of steam or drips of water to throw off the combustion

No.
The fan mod is not necessary. The OEM fan will do - those are just annoyingly loud and not very efficient/not high quality. I also don't think anyone changes the way they wake surf or stop based on whether or not the fan is used.

If someone can pull a plug when the issue pops up it may shed some light. Its a lot easier than installing fans

So far, turning the fan ON when stopped and bringing throttles into dead "neutral" position (when engines are cut) has alleviated (solved?) the issue.
It is easier to turn the fan on (than pull plugs from a hot engine while breaking in the middle of wake surfing session). What would I be looking for? Water? I don't think so.


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[Julian]

Keep in mind it doesn't have to be just one issue. It is possible that there are two or more factors working here. The water box may be filled with more water than usual causing greater exhaust backpressure, AND the engine may be starving for air. Turning on the blowers may provide enough extra power for the engines to overcome the backpressure.

Has anyone not found that turning the blowers on solves the problem?

 

[swatski]

The water box may be filled with more water than usual causing greater exhaust backpressure, AND the engine may be starving for air. Turning on the blowers may provide enough extra power for the engines to overcome the backpressure.

I agree, back pressure is very likely to play a role.
Something à la exhaust flap could help, etc. But I am going to leave it alone for now.
I would replace the factory fans with quality fans if I could find an exact replacement for the OEM. Spal 4" fans are different design.

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[Buckeye Boater]

Just remember both engines are at the same angle regardless so it can't be the angle of the engine as it would effect both engines equally. Just remember the old trick sticking a potato in a cars exhaust pipe will keep it from running same principal .

I had this problem last night just once while surfing, but I noticed a gas smell from the exhaust that i normally don't notice so running rich is definitely it.

 

[Cobra Jet Steering LLC]

Hmm fuel injectors do not care about the Angle I thought we determined that if you start the top engine and get the boat moving justa few miler per hour this would relive some of the backpressure on the exhaust system and then you start the low engine once the boat is moving forward.
I recall people trying this and it was working. The smell is due to the normal amount of fuel being dumped in the engine but it can not breath correctly due to excessive back pressure so this is just a symptom air can not be drawn in to the engine if it can not get out of the engine.

 

[Cambo]

I was at a boat party two weeks earlier and someone swam up and asked if I could help them get their boat started, it was a 2006 ar230 that was tied up to another couple of boats one had a DJ cranking out tunes earlier in the day they had a lot of people on the boat 15-22 dancing and partying the back swim platform was dipping under water very similar to being loaded with ballast . First thing I did was pull one of the spark plugs turned it over and water mist blew out. As you submerge the boat the water can back fill similar to towing to fast with out clamping the water lines . There is no water lock on the water cooling lines take some measurements you will be very surprised at how close the motor is to being under the water line if water is on the back swim platform its close and with some rocking and water pressure it can easily splash into the cylinders causing the hard start

I put the plug back in just gave it a quick bump and it fired up but then the poor guys scupper broke I told him to beach it. Surfing looks fun but be careful on how much ballast is used

 

[swatski]

This sounds a little strange:

First thing I did was pull one of the spark plugs turned it over and water mist blew out.

Are you saying you have had an engine with water in cylinders...

I put the plug back in just gave it a quick bump and it fired up

And yet it starts right away?
Was it one or both engines - hard to start? Both should be equally waterlogged, no?

But besides that... This just does not sound like a familiar scenario for my wake surfing... lol:

they had a lot of people on the boat 15-22 dancing and partying the back swim platform was dipping under water very similar to being loaded with ballast

I understand what you are trying to say but this is a little extreme...
It takes about 1,000-1,500lbs of ballast to get a good list, and a corner of the swim platform is submerged.

We fill, we surf, we empty.

And here is the deal:
Since I started routinely running the blowers and paying attention to shutting the engines off with throttles in "neutral", and a short cooling off before hand - we have had ZERO issues.

Hydrolocking those engines (via exhaust water ingress) is certainly possible, but it takes a whole lot more than sitting int he water... towing a boat or ski at planning speeds with the reverse buckets down, or running high pressure water hose (through the hull cap ports) with engines off - for several minutes to achieve that. Back pressure may play a role, albeit I'm leaning towards heat/air ventilation issues being the root cause.

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[Scottie]

Let's say that water did get into the cylinders... Wouldn't the only way to clear it be to remove the plugs and blow it out? I could be wrong on that, but if that's correct, then all of the cases where the engines recovered without removing the plugs would indicate there was no water in the cylinders... Right?

 

[Cambo]

This sounds a little strange:

Are you saying you have had an engine with water in cylinders... No it was another boater that asked for help I towed him to the shore because his scupper broke I think someone on the boat pushed on the hose and cracked the scupper while we were working on the engines

And yet it starts right away?
Was it one or both engines - hard to start? Both should be equally waterlogged, no? Both motors would not start

But besides that... This just does not sound like a familiar scenario for my wake surfing... lol:It does to me the wake side motor is the one with the problem because that side is being pushed under water

I understand what you are trying to say but this is a little extreme... Im picking up a new boat Thursday and will measure that is what Im really trying to explain is that the motor gets critically close to being below the water line
It takes about 1,000-1,500lbs of ballast to get a good list, and a corner of the swim platform is submerged.
Makes sense 20 people on board is over loading it by 8 to 10 extra people at is equal to that

We fill, we surf, we empty.

And here is the deal:
Since I started routinely running the blowers and paying attention to shutting the engines off with throttles in "neutral", and a short cooling off before hand - we have had ZERO issues. You are most likely slowing down and not chopping the throttle allowing the giant wave to dissipate and not force water into the system.

Hydrolocking those engines (via exhaust water ingress) is certainly possible, but it takes a whole lot more than sitting int he water... towing a boat or ski at planning speeds with the reverse buckets down, or running high pressure water hose (through the hull cap ports) with engines off - for several minutes to achieve that. Back pressure may play a role, albeit I'm leaning towards heat/air ventilation issues being the root cause.

I'm talking about a few drips of water throwing off the combustion mixture. The motor running hard and being hot could evaporate it




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[haknslash]

Idk. I think the blower resolves a lot of the issue. The water in cylinder theory just seems extreme because on a single engine boat the engine is in the center and not really getting lower in one side vs the other like a twin does. Lots of ballasted Yamaha's and you don't really hear of hydrolocked engines due to water in the cylinder from sitting. What does seem to absolutely work for me and many others is to run the blower. So there is something to the heat / vapor lock. Vapor lock has been an issue for many Wake boats as well giving them the same exact hard starting issue. They usually resolve this by dumping their ballast if they plan to sit for a while or they pour water on their fuel pumps to bring the temps down.

 

[MidnightRider]

Yeah I'm having a hard time buying that water can flow up into a cylinder through the exhaust simply if the lower swim platform is under water from people standing on it - if that is what you are trying to say. You also have to remember that the exhaust doesn't go straight from the exhaust output into the engine as you diagram indicates, the exhaust is piped upward nearly to the top swim platform and back down into the water boxes.

 

[Cambo]

Yeah I'm having a hard time buying that water can flow up into a cylinder through the exhaust simply if the lower swim platform is under water from people standing on it - if that is what you are trying to say. You also have to remember that the exhaust doesn't go straight from the exhaust output into the engine as you diagram indicates, the exhaust is piped upward nearly to the top swim platform and back down into the water boxes.

Its the water cooling line that has no water lock and its relation to the water level . My theory is that it can back fill into the exhaust manifold and the rocking motion causes it to splash up into the cylinder not enough to cause it to hydro-lock but enough to throw off the combustion mixture. If you take water in a hose and rock it just slightly it moves dramatically in the hose. I will show the measurement later in the week of the top of the highest point of the cooling lines in relation to the lower swim deck. As the boat is pushed down from ballast these motors are very short and at some point will be below the water line.

under normal operation on plane the jet nozzle is out of the water ,(Thanks jet boat pilot great video) the water pick up line is in the jet nozzle at idle this is below the water line but load up ballast and it gets pushed very deep under water especially when the boat comes to a stop when the wave washes up on the back deck add in the extra pressure of water. This water gets forced into the exhaust on the opposite side of the water lock




Below is the dimension in question the height of the swim platform in relation to the highest point in the cooling system

 

[MidnightRider]

Its the water cooling line that has no water lock and its relation to the water level . My theory is that it can back fill into the exhaust manifold and the rocking motion causes it to splash up into the cylinder not enough to cause it to hydro-lock but enough to throw off the combustion mixture. If you take water in a hose and rock it just slightly it moves dramatically in the hose. I will show the measurement later in the week of the top of the highest point of the cooling lines in relation to the lower swim deck. As the boat is pushed down from ballast these motors are very short and at some point will be below the water line.

under normal operation on plane the jet nozzle is out of the water ,(Thanks jet boat pilot great video) the water pick up line is in the jet nozzle at idle this is below the water line but load up ballast and it gets pushed very deep under water especially when the boat comes to a stop when the wave washes up on the back deck add in the extra pressure of water. This water gets forced into the exhaust on the opposite side of the water lock

View attachment 81515


Below is the dimension in question the height of the swim platform in relation to the highest point in the cooling system

View attachment 81517

Oh so your contention is that is being force back up the cooling water intake. I misunderstood.

 

[tdonoughue]

I think @Cambo 's theory is a good theory. Well-reasoned and well-thought out. For me, though, let's assume that there is that little bit of water in the cylinder that is not enough to hydrolock. If that happened, wouldn't the first or second crank of the engine force the rest of that out pretty quickly? I mean, I have cranked on that for a while with no sputter or anything indicating partial combustion. I think during that any water would be expelled and the puppy would start. No?

 

[Cambo]

If you pull the spark plugs it will blow out the guys boat that was having the problem starting from all the people on it would not start after multiple attempts on both motors. I pulled one plug cranked it over and it blew out water mist and fuel put the plug back in I was going to pull them all but just tried to start it and it fired . But the damn scupper broke and it started flooding the engine compartment . Again it was a 2006 but the water cooling is similar .