Trouble Turning over

[Drake92]

Good morning everyone. I am having some issues with my 95 seadoo XP 717. It started with a simple bad starter. I pulled the ski replaced the starter and went out for a test run. I had absolutely no power and blew a huge cloud of blue smoke. Shut it off next thing you knew it wouldn’t start. Would crank 1/4 turn then the starter would hum. If I pull the spark plugs it turns over fine. With plugs sometimes cranks sometimes doesn’t. The dealership told me it sounds like a rotary valve issue. I planned on pulling the engine anyways for other things anyways so I went ahead and pulled the motor. If y’all have any suggestions please let me know.

 

[Tyman2020]

1. check compression
2. Aftermarket cheap starters are exactly that CHEAP
3. i don't see you messing the rotary valve as it is a plate that rides on a plate. (it is possible) but to happen all of a sudden i would say you would have to ingest something into the motor. (water,Debris etc)
4. pull the rotary cover and check clearances and make sure its not warped

 

[Drake92]

I will do what you suggest. I didn’t get a cheap starter. I went to a seadoo dealership and purchased a remand starter directly from them. I’ll check compression but I just had the crank con rods wrist pins and pistons all replaced so for those to go out after 1 season would just suck. This will be the first time checking a RV. What are the clearances supposed to be and do you just use feeler gages to check that

 

[Drake92]

Ok so I checked the RV and it seems alright I re timed it and put it back together. I then did a compression test with a known good gauge and #1 had 60 psi and #2 had 70. Here a couple pictures of the head and cylinders if you wanted a look. Any help would be appreciated.

 

[Russellbugg007]

Aww no. Rebuild time . 150psi is new , will run in the water as low as 118 iv seen..

hopefully you can figure out why it happened . You pre mixing or injected ?

 

[Drake92]

I’m injected. But I pulled my pump and bought the conversion kit and going to pre mix

 

[Drake92]

I did pull it all apart and I found a broken ring on #1 cylinder so that kinda explains low compression there but couldn’t found anything wrong on #2 at all

 

[Burner71]

when was the last time you greased the drive shaft bearing?
When my starter began having issues it turned out to be the bearing locking up on the shaft.

 

[Ckrawiec]

when was the last time you greased the drive shaft bearing?
When my starter began having issues it turned out to be the bearing locking up on the shaft.

Possible sure...but he said it turns over fine with no plugs, so that's a clue that its probably not the shaft bearing.....anywho, broken piston ring found.....there are other issues afoot. The original description indicated a "cloud of blue smoke"....which indicates burning lots of oil which typically points to a ring problem (far as I've ever been taught/experienced)

 

[Burner71]

Possible sure...but he said it turns over fine with no plugs, so that's a clue that its probably not the shaft bearing.....anywho, broken piston ring found.....there are other issues afoot. The original description indicated a "cloud of blue smoke"....which indicates burning lots of oil which typically points to a ring problem (far as I've ever been taught/experienced)

Mine turned over fine also without plugs.
The pressure with the plugs in and a bearing starting to seize will keep the starter from turning or will release the clutch before it turns.

 

[Ckrawiec]

Mine turned over fine also without plugs.
The pressure with the plugs in and a bearing starting to seize will keep the starter from turning or will release the clutch before it turns.

As I stated, certainly a possibility....but IF the machine cranks and turns over OK without plugs that tells me the bearing is not seized/seizing enough to keep the crankshaft from turning the drive shaft...correct? so how could then putting the plugs in make the bearing suddenly strong enough to stop the driveshaft ( & crankshaft) from spinning? That doesn't add up in my book...putting the plugs back in could cause the pressure increase to stop the crankshaft from spinning (due to whatever conditions are not occurring that is preventing combustion in the piston chambers (but that's a story for another day). Personally, I would least suspect the shaft bearing under these conditions....but ski's do play tricks on us, especially the older ones for sure.

 

[Burner71]

As I stated, certainly a possibility....but IF the machine cranks and turns over OK without plugs that tells me the bearing is not seized/seizing enough to keep the crankshaft from turning the drive shaft...correct? so how could then putting the plugs in make the bearing suddenly strong enough to stop the driveshaft ( & crankshaft) from spinning? That doesn't add up in my book...putting the plugs back in could cause the pressure increase to stop the crankshaft from spinning (due to whatever conditions are not occurring that is preventing combustion in the piston chambers (but that's a story for another day). Personally, I would least suspect the shaft bearing under these conditions....but ski's do play tricks on us, especially the older ones for sure.

well i can only tell you from direct experience. An under-greased bearing will start to create enough drag to cause the starter to over-run or stall. Take the plugs out it will turn all day like like nothing is wrong, put them in and it will do the same thing. Learned this the hard way by replacing 3 starters thinking they were all bad until i noticed the carrier bearing one day trying to turn with the shaft.

 

[Ckrawiec]

well i can only tell you from direct experience. An under-greased bearing will start to create enough drag to cause the starter to over-run or stall. Take the plugs out it will turn all day like like nothing is wrong, put them in and it will do the same thing. Learned this the hard way by replacing 3 starters thinking they were all bad until i noticed the carrier bearing one day trying to turn with the shaft.

No arguments with direct experience....all these skis are tricky b'tards....they will keep you humble and always guessing. Persistence and perseverance are the keys to success OR disposal.......but it really depends on how long your wallet can hold out

 

[Drake92]

I grease it every year before I put it in. I did realize the starter is still turning with the fly wheel when I turn it over by hand us this normal. I know at least for cars and my boat.

 

[mikidymac]

No. The starter should not be engaged when turning the engine by hand.

 

[Ckrawiec]

I grease it every year before I put it in. I did realize the starter is still turning with the fly wheel when I turn it over by hand us this normal. I know at least for cars and my boat.

AS Miki has indicated...the starter should NOT be engaged to the flywheel when turning over by hand.

The starter bendix should ONLY shoot out to engage the flywheel if it gets direct power from the battery (through the solenoid), otherwise the starter bendix should be retracted away from the flywheel under normal circumstances. IF the bendix is engaged all the time...that is not normal.