Engine won’t start when hot

[FSH 210 Sport]

Had a Scarab. Sold it and have had the 242x for 3 years. I usually cruise into the no wake zone in no wake mode where we tie off or anchor out and that never makes a difference. The boat is firing. It will try to start, but sputter and fail. Sometimes you have to crank it numerous times before it will finally keep running. This is definitely temperature related. I don't see how the pickup coil could be out of spec when it starts first crank every time cold, and also every time hot after it finally starts.

Because the Ohm value of the winding in the pick up coil is changing due to heat, crank position sensors do the same on their way to failure. Having said that, even when cold a bad pick up coil will be out of range when cold. You’ll need a shop manual and a good ohm meter to test the pick up coil, check it cold then check it if the engine doesn’t want to start. The symptoms you describe of how it is getting worse are a bit classic for a failing pick up coil from what I’ve read here. Check it and eliminate it as a possible cause.

Try the no wake mode at level three in neutral for 15 seconds then back to idle then shutdown once you’ve stopped just to be sure.

 

[Jet Boat Brant]

Because the Ohm value of the winding in the pick up coil is changing due to heat, crank position sensors do the same on their way to failure. Having said that, even when cold a bad pick up coil will be out of range when cold. You’ll need a shop manual and a good ohm meter to test the pick up coil, check it cold then check it if the engine doesn’t want to start. The symptoms you describe of how it is getting worse are a bit classic for a failing pick up coil from what I’ve read here. Check it and eliminate it as a possible cause.

Try the no wake mode at level three in neutral for 15 seconds then back to idle then shutdown once you’ve stopped just to be sure.

Ok I'll give it a shot. I honestly think that if I never start the boat, just turn the key on and let it sit for 3 hours in float mode it will have the same problem, but I haven't tested that theory. In my mind after getting it to start, then immediately shutting it off it should be hard to start again because the temperature is still there, but it starts right up with zero hesitation. It is the weirdest thing.

 

[FSH 210 Sport]

Ok I'll give it a shot. I honestly think that if I never start the boat, just turn the key on and let it sit for 3 hours in float mode it will have the same problem, but I haven't tested that theory. In my mind after getting it to start, then immediately shutting it off it should be hard to start again because the temperature is still there, but it starts right up with zero hesitation. It is the weirdest thing.

Keep at it I know you can solve the riddle !

 

[David Martin]

How does the starter sound and sorry if this has been ask I did not re-read all five pages. I had a starter get heat soak once drove me crazy started easy cold and then hot would turn over slow............... then shut it off and then a quick restart hot it was all over the map.

 

[Julian]

Do you run it with the blower on? Some boats have leaks in the exhaust that once you run it for a while starves the engine of air. Also, some people have accidently blocked the air intakes either just with "stuff" or by actually intalling speakers into the holes. I didn't read all the pages on the thread, so maybe you've already eliminated this as a possibility.

 

[suke]

When I've run into these issues I have found leaving the engine hatch open even for 5 minutes is enough to cool everything down to fire right up.

 

[Jet Boat Brant]

How does the starter sound and sorry if this has been ask I did not re-read all five pages. I had a starter get heat soak once drove me crazy started easy cold and then hot would turn over slow............... then shut it off and then a quick restart hot it was all over the map.

Mine cranks super fast, and tries to start so it's firing.. It just takes multiple tries to get it to start.. I'm going to try the blowers, and opening the hatch to see if it helps.

 

[David Martin]

Starters sounds good .....................I had a hard starting engine that fired but just took a long time start also............Plugs were carbon black and vary carbon up on 2 plugs turned out to be dirty/corroded fuel injectors. Cleaned injectors ,new plugs all was back to normal. A stumbling engine/start just barely firing is usually a weak spark, or air fuel ratio is not proper .....................(air, injector, weak spark) any of the 3 can mess with a quick start.

 

[Jet Boat Brant]

Starters sounds good .....................I had a hard starting engine that fired but just took a long time start also............Plugs were carbon black and vary carbon up on 2 plugs turned out to be dirty/corroded fuel injectors. Cleaned injectors ,new plugs all was back to normal. A stumbling engine/start just barely firing is usually a weak spark, or air fuel ratio is not proper .....................(air, injector, weak spark) any of the 3 can mess with a quick start.

I've already swapped plugs, no change. They looked new when I pulled them. Not bad at all. Haven't messed with the injectors yet.

 

[David Martin]

If the plugs have been in a while and they look good not black all carbon upped, then the injectors might not be the problem. I would start to look at the ignition and the air supply. The ignition is the pick up coil then the coils on the plugs. The EMC can also is involved in the start.........the computer takes info from various sensors like the cam position and the Air flow sensors (MAP) and sets the Timing and the EMC then gives info/pulse to the injectors to maximize the (air fuel ratio) for an easy start. Different info for cold or hot start.

The air supply is the filter but most important is the Throttle body it opens via electric commands from the throttle and other sensors ect..........This Throttle body helps in controlling the air fuel ratio for easy starts.

Just a few things to check out all these parts, you will need a voltage/ohm meter also need a peak voltage tester. The peak voltage around 32 dollars voltage/ohm meter from 8 bucks and up and throw in a set of small alligator clips 5 bucks . Service manual describes how to do all these test and most are easy with the manual. Not sure how easy it is to get a 2020 manual.....my 2013 was easy and cheap around 35 dollars for electronic copy that I could Print myself..........I'm old school I like the printed version.

Last is the fuel pump if its not doing its job like low pressure maybe a clog fuel filter or weak pump.......then the fuel air ratio is not going to be correct.

Hope this helps Sorry for the book

 

[Jet Boat Brant]

If the plugs have been in a while and they look good not black all carbon upped, then the injectors might not be the problem. I would start to look at the ignition and the air supply. The ignition is the pick up coil then the coils on the plugs. The EMC can also is involved in the start.........the computer takes info from various sensors like the cam position and the Air flow sensors (MAP) and sets the Timing and the EMC then gives info/pulse to the injectors to maximize the (air fuel ratio) for an easy start. Different info for cold or hot start.

The air supply is the filter but most important is the Throttle body it opens via electric commands from the throttle and other sensors ect..........This Throttle body helps in controlling the air fuel ratio for easy starts.

Just a few things to check out all these parts, you will need a voltage/ohm meter also need a peak voltage tester. The peak voltage around 32 dollars voltage/ohm meter from 8 bucks and up and throw in a set of small alligator clips 5 bucks . Service manual describes how to do all these test and most are easy with the manual. Not sure how easy it is to get a 2020 manual.....my 2013 was easy and cheap around 35 dollars for electronic copy that I could Print myself..........I'm old school I like the printed version.

Last is the fuel pump if its not doing its job like low pressure maybe a clog fuel filter or weak pump.......then the fuel air ratio is not going to be correct.

Hope this helps Sorry for the book

What doesn't make sense about ignition is that after it finally starts and you kill it, it will start without struggle every single time until you let it sit not running for awhile. It's a heat soak fueling thing I believe. I think once the vapor lock is cleared it will keep on starting.

 

[FSH 210 Sport]

What doesn't make sense about ignition is that after it finally starts and you kill it, it will start without struggle every single time until you let it sit not running for awhile. It's a heat soak fueling thing I believe. I think once the vapor lock is cleared it will keep on starting.

Did you try the running at no wake level three in neutral then back to idle before shut down yet? If not you should try that first before going so deep. When you get to a stopping point and are in neutral raise the rpms by going to no wake level 3, do a 1 Mississippi 2 Mississippi count to 15, then reduce back to normal idle and shut the engines off. All of the symptoms and possibilities you describe have been covered in other threads with the only solution being the no wake level three thing, or replacing the pick up coil. Could it be something else? Sure, but this is the simplest solution.

 

[itsdgm]

What doesn't make sense about ignition is that after it finally starts and you kill it, it will start without struggle every single time until you let it sit not running for awhile. It's a heat soak fueling thing I believe. I think once the vapor lock is cleared it will keep on starting.

To me, it Sounds like a fuel injector is leaking fuel into the cylinder. Short shut down, small amount of fuel leaking into cylinder/s, it fires right up. But sitting for a longer period of time, it getting flooded.

Maybe swap fuel injectors from engine to engine and verify.

Hope you figure it out soon.

 

[dzeppos]

I think this technique works. I was at Big bear all last week (6800 altitude) wake surfing and other water sports in heavy use. Running in neutral in no wake mode for 10-15 seconds work. So does wake surfing with the blowers on. If you do get this stall condition - then simply opening the hatch for 1-2 minutes solves it. I started having this issue about 3 years ago and it became a frequent topic over the past 2-3 years. I don't recall this issue coming up from 2016-2021. Is it the gas, or some other common condition that's causing this issue?
the remedies work but really curious on why this is happening.

Otherwise, can't complain for a boat with 410+hours that has been mostly problem free

Did you try the running at no wake level three in neutral then back to idle before shut down yet? If not you should try that first before going so deep. When you get to a stopping point and are in neutral raise the rpms by going to no wake level 3, do a 1 Mississippi 2 Mississippi count to 15, then reduce back to normal idle and shut the engines off. All of the symptoms and possibilities you describe have been covered in other threads with the only solution being the no wake level three thing, or replacing the pick up coil. Could it be something else? Sure, but this is the simplest solution.