Seadoo GTX 787 Starting/Timing help

[Seadoosam]

Just picked up a 787 GTX. These are the symptoms it is having:

Very very slow cranking. Starter struggles to get past the compression point very often. It will unreliably kick over and crank normally with a just charged, perfect agm battery, but that is it.

Already checked all the electrical connections themselves to the starter, coil, etc and changed out the 2 positives and one negative. Also put power directly to the starter and it hesitated and then cranked a bit slow.
When it does decide to start it is revving very hi at 4k rpms. it is very hard to turn the engine by hand at a certain point. Compression gauge says 140 PSI. It also starts extremely fast like within the first half a crank when it does start and it usually backfires.


I think the timing is just a little off. Do you agree?

Which timing problem should I look at? Is it the rotary valve I need to check or the stator? I’m not sure. Any other input appreciated! I tried to be as detailed as possible! It is my belief this engine was just rebuilt due to the compression and the ski having very high hours. Im guessing the PO couldn’t figure it out after rebuilding it and dumped it

 

[etemplet]

I'd check the brushes on the starter after I pulled the spark plugs and turned the engine over. If you have a leaking inner oil seal on the crank oil will end up in the cylinders making the ski difficult to turn over. A compression check is one of the first things I do. Worn brushes on the starter prevent it from getting to full power. You could have a bad solenoid or bad wire to the starter or a bad ground. I wouldn't look at the engine untill I elimiated everything else. Good Luck

 

[Seadoosam]

I'd check the brushes on the starter after I pulled the spark plugs and turned the engine over. If you have a leaking inner oil seal on the crank oil will end up in the cylinders making the ski difficult to turn over. A compression check is one of the first things I do. Worn brushes on the starter prevent it from getting to full power. You could have a bad solenoid or bad wire to the starter or a bad ground. I wouldn't look at the engine untill I elimiated everything else. Good Luck

I have checked/swapped the solenoid and the wires and checked and cleaned all the grounds. Havent pulled the starter out to check yet. are worn brushes obvious to spot? I haven't looked into starters before really

 

[etemplet]

Depending if th Starter is OEM you could just have a weak/bad starter. Most brush issues are easy to spot, look for anything going to ground, dirty armature, broken or loose magnets, etc... I always open the starters up, saves me surprises.

 

[Seadoosam]

Depending if th Starter is OEM you could just have a weak/bad starter. Most brush issues are easy to spot, look for anything going to ground, dirty armature, broken or loose magnets, etc... I always open the starters up, saves me surprises.

Yea starter has stopped working altogether now. I am getting voltage according to the meter after the solenoid when the button is pressed so I think the starter is just gone at this point. I think you are right. Going to rip it out tomorrow and assess! I will keep the thread updated!

 

[Seadoosam]

Update: A new starter cured all the starting problems!.