Warm start problem - Resolved

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I have not read where anyone has really had a problem like this resolved, but I am going to put it out there to see if any of you smart guys know where to look.

I have a 2012 Seadoo Speedster 150 HO

I recently had the motor rebuilt and since I got it back, the boat has been hard to start when warm. I have full power and it runs very smooth on the water.

The symptom is as follows. I push the start and the starter starts the motor but it immediately stalls almost as if the RPMS are too low. Then I hit the start button again and it takes about 2 or 3 seconds and the motor starts and it sounds like it might stall at first but then it idles normally and all is good. Sometimes I smell the exhaust right after the start and it smells rich like unburned fuel. There are never any error codes thrown. I checked everything with the CanDoo and it all seems fine.

This will happen every time until the next day when everything is cold and it will start normally.

In the process of fixing this and from some recommendations I have replaced the following.

Fuel Pump
Throttle body

So, to summarize. Boat runs fine and performs as expected but it is abnormally hard to start when warm and this all started after the rebuild. (guy who rebuilt it is never available so there is no going back to him)

Any Ideas? I was thinking may be the MAT sensor but......I am not sure if that would even cause this problem.
Have you tired opening the fuel cap when this happens? Have you pulled plugs after the hard start?
Have you tired opening the fuel cap when this happens? Have you pulled plugs after the hard start?

I have and there is no pressure release when it happens. Even if that was the issue, I would think that I would be fuel starved on high throttle. I have pulled and replaced the spark plugs on the water and it didn't change anything. They look great too. Nice brown color to them.

This is the only issue that I have with the boat and I really wish someone could point me in the right direction.
How long are you running the blower before the warm start? Might be really hot air in the engine compartment.
I agree that it is very warm in the engine compartment and perhaps this could be an issue. I will test this out tomorrow. However, why would this problem have surfaced only after a rebuild. The fuel line is only a couple feet long and does not run next to motor. Where would I be vapor locking?

Thank you for the ideas. I will report back with what I find.
I took boat out yesterday and ran it most of the afternoon. It starts perfectly cold (although the idle jumps around when it is first started). It had full top end and is very responsive with no hesitating. It actually runs perfect just like when it was new. I stopped several times and went to restart after running the blower motor, lifting the bilge over until it was filled with cool error, opening the gas cap to ensure that there was no pressure built up and it is always the same thing. Go to start and the motor almost starts but doesn't. Then hit the start button again and it cranks for about 2 seconds and then it starts. I guess I can live with the problem, but I know that it is not right and something has to be causing it. Any other ideas??
Update to this.

I saw a post on another site where someone that had a similar problem on their PWC. Several people said to check battery and connections. I have done that. I have two batteries and the connections on them are good.

I mentioned that this motor was recently rebuilt.

I would have assumed that the person that rebuilt it would have made sure the ground was good on the motor. Well, it was not tight and it was not clean. I removed the ground from the motor, took a wire brush to the motor where the grounds connect, and cleaned the cable. That cable is about 3' long and is 6awg. I decided to run an additional 4awg ground cable from the battery to the motor as well.

Now...I have a great ground connection, no doubt about it. I tested cold and the boat started, as it always has. The difference is that now, the starter seems like it has so much power and cranks very fast. I forgot that it should crank like that. It is dramatically different.

I am almost positive that the problem I was chasing with hard warm starts was because the starter was not getting enough current due to a bad ground on the motor.

I am going to run it this weekend and report back.
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