951 fouling plugs and poor response but has top end?

[awward]

Hey guys,

I have a GSXL that's been causing me some trouble all summer. I've gone through quite a few troubleshooting steps so far and there hasn't been much of an improvement yet.

So the issues I'm having are poor throttle response off idle and the thing fouls plugs in about 15-20 minutes. The carbs have just been rebuilt with genuine parts, jets are standard, needles are new with new o-rings and set to 1 1/4 L and 0 H. raves are clean, engine was redone by the previous owner but has mediocre compression.. Maybe 115psi.. This could be my issue as well but hoping not.

A quick question on this.. If the squish is excessive could that cause a 20psi drop in compression? verifying squish is on the to-do list...

Also, the engine seems to run quite hot. the exhaust pipe is almost too hot to touch whereas on my other GSXL's its hot but only a bit.


On my to-do list is to verify RAVE operation, verity squish, and check exhaust gaskets and ports to make sure silicone from PO didn't plug something up. That's pretty much it. Any other suggestions? Just looking for things to check out here as I'm pretty stumped.

Thanks in advance! If any of you want to know any more info or have me answer questions about the ski just let me know and I'll do my best.

 

[1of500]

If it was mine I'd tear it down. I don't trust previous owners rebuilds.

 

[awward]

He had receipts from wsm and photos of the whole thing. I believe the engine was properly rebuilt but maybe not, who knows.. haven't torn it apart yet. I'll get an inspection camera down there this week and see how things look.

 

[1of500]

It's the little things. Squish, pressure test lube on new assembly then reconnecting the cooling system which is what is making your pipe hot he has something crossed

 

[awward]

Yeah beginning to think the engine having poor compression may be causing me most of my issues. Supposed to rain after work today so further inspecting will have to wait.

I've checked the cooling lines many times though. Everything looks correct. I've referenced other skis and the factory diagrams. Could a bad water box valve not be sending enough water to the head pipe? I know one of the feeds has to go through that valve first.. Any way to test it?

 

[POPPS]

Your compression is way low,,,but within 10% of each other,,,the ravs are mushy because of poor combustion/compression,,,the squish for a non race boat is irrelevant.

 

[awward]

Sounds like a top-end is in my future...

 

[RSteeves]

Adjust your oil cable. It's getting too much oil. The hash marks on a 951 are REALLY hard to see. I used a camera. I had the same problem when I went thru my carbs...

Good luck!

 

[POPPS]

I would load test the battery,,and check for a nice spark.,a slightly weak battery can give you a slightly weak spark and foul the plugs,,,happened to me once,,dropped in a new battery and she ran like a champ,

 

[awward]

Hey guys thanks for the replies.. A bit of an update:

I thought my raves were functioning but they were in fact remaining closed. the solenoid works as it should like I thought and they were just cleaned and hold pressure/vac but the pulse line coming off the crankcase had nothing. replaced the check valve with an OEM one, cleaned the line, and the raves are back in business!

Double checked compression and it's at 120/120. Not the greatest but not the worst either.

The oil pump is confirmed to be adjusted properly.

The battery is brand new as of a month or two ago and has ample cranking amps.


I'm pretty sure the raves were my issue just like the other 951 thread... oh well more info out there - sort of. I could have sworn I confirmed they were working but I guess I was wrong. It's been rainy here the last few days so I haven't been able to get out and test it. Hopefully tomorrow or Thursday!