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

[Scottie]

This looks so good. Would you be so kind to post a link to the blowers, albeit I realize those may not be doable in 240s as the aft bulkhead is totally different, but they might fit.
I'm assuming you are having them both blow out, correct?

Absolutely. Here's the fans I picked up from summit racing. These are the same ones @gmtech16450yz used, best I can tell. https://www.summitracing.com/parts/spu-ix-30103013

I cut the holes with a 6" hole saw. That was the trickiest part. I really needed a 5.75" hole saw, and I'm not sure you'll find one of those. It worked out fine, but my bolt holes were actually touching the 6" hole, and there's just a little space around the outside fan ring. A slightly smaller hole saw or a slightly larger fan would have been just a bit better. I cut the factory blower connector off one of the blowers and wired both fans to it, so it connects just like it did originally, controlled by the blower switch.

 

[SamCF]

Vaporlock sounds like the likely culprit. Its always the port side engine. That engines fuel system is fairly close to the other engines exhaust. I know the exhaust is fully jacketed, but if you shut down a hot motor, it will heat thru that very quickly.

I have a cold air intake that runs down the exhaust side of the engine then up to the fresh air intake. This pipe gets incredibly hot if I shut down with a hot motor. That is right where the fuel lines are on your port engines.

Run a high idle and check your coolant pissers. See how long it takes for the water to go from scalding hot to warm. That's how long you need to run to cool down.

Those fans will definitely help if this is the problem.

 

[Cambo]

Vaporlock sounds like the likely culprit. Its always the port side engine. That engines fuel system is fairly close to the other engines exhaust. I know the exhaust is fully jacketed, but if you shut down a hot motor, it will heat thru that very quickly.

Run a high idle and check your coolant pissers. See how long it takes for the water to go from scalding hot to warm. That's how long you need to run to cool down.

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Has anyone pulled a spark plug? its a very simple task with the motors being hot and the exhaust well below the water line what is the possibility that water is hitting areas of the exhaust that would normally be much higher creating steam vapor that works its way back into the cylinder. The moisture mixing with the combustion could be the problem of hard stating pull one plug from each motor and see if they look identical. Hopefully they don't look like the picture below

 

[swatski]

Has anyone pulled a spark plug? its a very simple task with the motors being hot and the exhaust well below the water line what is the possibility that water is hitting areas of the exhaust that would normally be much higher creating steam vapor that works its way back into the cylinder. The moisture mixing with the combustion could be the problem of hard stating pull one plug from each motor and see if they look identical. Hopefully they don't look like the picture below

Very good point.
However, at least in my boat the intakes are a good foot+ above the water even with the most amount of ballast and list. I need to take some pics on the water next time.

If cooling the engines, before turning them off, along with bringing the throttles into dead-center-neutral and evacuating compartment heat with good blower action cures the issue hopefully we won't have to worry about that scenario.

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[Scottie]

Update on this issue. I haven't experienced the restart issue again at all. We've had at least 4 full days of surfing since I installed the fans, under the same conditions that I experienced the problem in before. It's hard for me to definitively say the issue was heat related, and that the fans resolved it. BUT... it hasn't happened since. With no temp gauge, I don't have any hard data. I also wasn't running the factory blowers while surfing before, and I am running the new fans while we surf now. So it's possible it did resolve it, but running the factory blowers may have resolved it also. Either way, I can say that airflow through the engine compartment is SUBSTANTIALLY increased, and air temp inside the engine compartment is noticeably lower. Also, the engines seemed to gradually develop a rich condition after surfing for a while, sometimes to the point of smelling fuel in the exhaust. This seems to have disappeared as well, presumably due to better airflow.

 

[swatski]

Also, the engines seemed to gradually develop a rich condition after surfing for a while, sometimes to the point of smelling fuel in the exhaust.

This is concerning, isn't it? Could this be due to "heat soak"? I've heard some 2 strokers can suffer from that and blowby?

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[swatski]

@Scottie As I said in the other thread:
I'm starting to lean towards the blower/quasi-vapor lock(?) hypothesis more and more. I have been turning the blower on at every break when surfing (albeit I try not to turn the engines off if I can keep them at least idling - for better cooling) - and no issues. One exception, when I spaced out and did not have the blowers going - hard start again. This is not any proof but to me indicates strongly that a better air flow between hard runs may be just what the doctor ordered...

Now - the question is: how to do this in a new 240? I may need to look for replacement blowers that are more efficient and quiet as there is not room for bigger cut outs, the air path is pretty tortuous in the 240s...

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[Scottie]

This is concerning, isn't it? Could this be due to "heat soak"? I've heard some 2 strokers can suffer from that and blowby?

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I don't know if it's concerning necessarily. Heat is the enemy of basically all things, and when the motors are pegged out and we're only doing 10mph, I'm just not sure there is ample airflow to get fresh air to the engine, especially with the swim deck bag causing at least some restriction, as you've mentioned. My engines have never overheated, at least according to the lack of an "overheat" warning. I think it was more of an air fuel mixture kind of thing. Heat soak is probably accurate, like you said, but at a much smaller degree than what the supercharger guys deal with.

 

[Scottie]

@Scottie As I said in the other thread:
I'm starting to lean towards the blower/quasi-vapor lock(?) hypothesis more and more. I have been turning the blower on at every break when surfing (albeit I try not to turn the engines off if I can keep them at least idling - for better cooling) - and no issues. One exception, when I spaced out and did not have the blowers going - hard start again. This is not any proof but to me indicates strongly that a better air flow between hard runs may be just what the doctor ordered...

Now - the question is: how to do this in a new 240? I may need to look for replacement blowers that are more efficient and quiet as there is not room for bigger cut outs, the air path is pretty tortuous in the 240s...

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Spal has some 4" fans also. Less air obviously but probably still much more than the factory blowers. Room for those?

 

[swatski]

I don't know if it's concerning necessarily. Heat is the enemy of basically all things, and when the motors are pegged out and we're only doing 10mph, I'm just not sure there is ample airflow to get fresh air to the engine, especially with the swim deck bag causing at least some restriction, as you've mentioned. My engines have never overheated, at least according to the lack of an "overheat" warning. I think it was more of an air fuel mixture kind of thing. Heat soak is probably accurate, like you said, but at a much smaller degree than what the supercharger guys deal with.

It is annoying there are not temp gauges but as long as enough water is running through the cooling system (and pissers are shooting water that is not hot) there is no risk of overtemp of the engine at any speed.
But - there is something else going on...

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[boudin]

Been reading this entire thread, and the theories are interesting.

I see the 2016 boats have a resonator. When you guys are full ballast, how high is the hose from the resonator to the water box--above or below the water line--the highest point in the loop? It does seem possible some water could be seeping back into the cylinders when the motor is turned off making it harder to start. It would also explain the fuel smell--the moisture is preventing the air/fuel mixture from igniting.

The blower is a good idea if you are smelling gas fumes. But I don't know how it would help otherwise, unless a sensor is reading too hot and causing the ECU to not fire the coils. Even then, you would think the ECU would not fire the injectors either.

I've not heard of sensor caused hot start issues with the 1.8. The pre-2012 Kawasaki 15Fs Jet Skis have this problem--the exhaust manifold sensor reads too hot and prevents the ski from starting. Pouring some water on the sensor solves the problem.

-Greg

 

[Scottie]

Been reading this entire thread, and the theories are interesting.

I see the 2016 boats have a resonator. When you guys are full ballast, how high is the hose from the resonator to the water box--above or below the water line--the highest point in the loop? It does seem possible some water could be seeping back into the cylinders when the motor is turned off making it harder to start. It would also explain the fuel smell--the moisture is preventing the air/fuel mixture from igniting.

The blower is a good idea if you are smelling gas fumes. But I don't know how it would help otherwise, unless a sensor is reading too hot and causing the ECU to not fire the coils. Even then, you would think the ECU would not fire the injectors either.

I've not heard of sensor caused hot start issues with the 1.8. The pre-2012 Kawasaki 15Fs Jet Skis have this problem--the exhaust manifold sensor reads too hot and prevents the ski from starting. Pouring some water on the sensor solves the problem.

-Greg

I'm with you. I don't really understand the problem, and it doesn't really make sense to me. Im also not sure why the blowers seem to help, but it does seem that way. As for the potential heat issue, air intake temp doesn't theoretically have a measurable impact on combustion until you get way up the thermometer... So all of that to say... I honestly don't know.

 

[swatski]

The blower is a good idea if you are smelling gas fumes. But I don't know how it would help otherwise, unless a sensor is reading too hot and causing the ECU to not fire the coils. Even then, you would think the ECU would not fire the injectors either.

That could be something...

As far as water in cylinders - it's extremely unlikely to be the issue.
First, the resonators are pretty high up in the bilge compartment, and the water path is broken in several places. The boat would have to be submerged for a while or significant back pressure would need to be involved such as in a case of towing too fast with back gates closed...
At least in my boat, I have had the hard hot start happen without excessive ballast where the swim platform is barely touching water.

It could be back pressure in the exhaust, but I am beginning to doubt this - based on the fact that running blowers seems to help.

Another observation is that if the engines are cut/stopped with the throttle engaged (not in "neutral" position) - that seems to correlate with hard starts as well. Flooding and too rich to restart?

I understand that vapor lock is unusual in a fuel injected engine as pressure in the fuel rail is high, more than enough to overcome the vapor pressure of gasoline even in a very hot engine compartment.
I'm sure it's very unlikely (albeit not impossible) that the vapor pressure in the fuel line in a heat-soaked engine could get higher than what the fuel pump puts out, but if the gasoline is heated by the heat of the engine, and somehow percolates the fuel into the throttle area - would it possibly be forming a mixture that is too rich to fire?

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[Jgorm]

When the fuel boils in the rails you go way lean. I experience this on my mustang all the time. I removed the valve that keeps pressure in the fuel line. After a short stop with a hot engine it is difficult to start. My fuel pump only primes for about 1 second. Sometimes i have to prime it 5x to build pressure. If i try and start it without the pressure, it will take extended cranks and stumble. It could be this in combination with more water in the exhaust that is the cause of the poor starts. Maybe the blower cools the rails.

 

[SamCF]

It's hot fuel rails. I had a turbo RZR that did the same thing. Shut it down hot and sit for 5 minutes and it wouldn't start. If I let the fan cycle and shut it down when the engine coolant had dropped to 185, it would start easily at any time.

 

[boudin]

It could be back pressure in the exhaust, but I am beginning to doubt this - based on the fact that running blowers seems to help

I never really bought into this theory myself. Seems unlikely.

Another observation is that if the engines are cut/stopped with the throttle engaged (not in "neutral" position) - that seems to correlate with hard starts as well. Flooding and too rich to restart?

This is good one. Are you able to replicate it? I'm wondering if the ECU has a problem with adjusting the fuel curve after the boat has been shut off at high RPM. If you can replicate this, try to turn your battery selector off, then on to kill all the power to the ECUs.

-Greg

 

[haknslash]

When the fuel boils in the rails you go way lean. I experience this on my mustang all the time. I removed the valve that keeps pressure in the fuel line. After a short stop with a hot engine it is difficult to start. My fuel pump only primes for about 1 second. Sometimes i have to prime it 5x to build pressure. If i try and start it without the pressure, it will take extended cranks and stumble. It could be this in combination with more water in the exhaust that is the cause of the poor starts. Maybe the blower cools the rails.

There was a boating thread I read a long time ago. I want to say it was on THT but anyways there were some members who had the same types of issues with their boats. One guy mentioned he gets wet towels and lays them over his fuel pump and rail and that cools them down enough for no hot start issues. Could be right. All I know is that any time I had this happen it was when I didn't use my blower. When it happened to Bill and I his blower wasn't on either. Ever since then I have run my blower if I'm going to be running the engine up high for surfing or running fast on the water and I haven't had it happen so long as the blower runs (knocks on wood).

 

[Scottie]

A number of people claim running the blower helps, and it definitely seems to have helped my situation as well. The only thing that makes sense to me in that case, is that the blower is keeping engine compartment temps low enough to prevent fuel from boiling in the rail. As far as it being port side only, someone mentioned earlier that the port side fuel rail is close to the starboard exhaust, so that's a large heat source that the starboard motor doesn't have to deal with. Unless the issue returns, that's what I'm going to go with. I might stick a thermometer in the compartment and see how much running the blowers reduces the temperature. I believe it is substantial.

 

[haknslash]

We have a FLIR thermal camera at my work that we use for fire tests. I never thought about it but I could bring it out and see if there is huge difference. A temperature gun could would work too.

 

[Cambo]

As far as water in cylinders - it's extremely unlikely to be the issue.
First, the resonators are pretty high up in the bilge compartment, and the water path is broken in several places. The boat would have to be submerged for a while or significant back pressure would need to be involved such as in a case of towing too fast with back gates closed...

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

Very good point.
However, at least in my boat the intakes are a good foot+ above the water even with the most amount of ballast and list. I need to take some pics on the water next time.

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




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




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