1995 GTX Intermittent Starting

[mkjj123]

I've been having this problem pretty much since rebuilding the entire machine, engine included (rebuilt by SES). Starts, runs great. then won't start. When it's ready, maybe hours, or even days later, it will start, run great, maybe start again, but eventually not start. A reputable shop has had it numerous times and it usually starts for them but there have been times that it hasn't. They rebuilt the carbs (again, since i did it during the rebuild), checked all the lines, fuel system, etc., and they are at a loss. The only trend (which may be a stretch) is that it seems that f we run it, bring it in to refuel, it won't restart. Wondering if opening the cap releases a vacuum or something, but it's a vented system so doesn't really make sense.

The ONLY thing the shop can find is that the compression isn't perfect; 140 PTO, 122 mag. They said they can open the top to see if there's anything obvious, and rebuild for $600-$800 (top end only, not the crank). I have so much into it at this point, plus the fact that my son and I rebuilt it and it's in great shape, that I'm ok putting another grand into it, but they aren't sure if fixing the compression will actually address the starting problem.

My question to you all is whether these compression numbers would cause the intermittent starting. Any other ideas what could be causing the issue?


Thanks!

 

[mwat65]

Your compression is way off. You can only be a few pounds difference from one cylinder to the other. It can cause a lot of things . At 122 it’s going to have trouble starting . You may have crinkled your gasket when u rebuilt it. Your going to have to rebuild it again. Check the cylinder base gasket when u pull the top.

 

[mwat65]

Without good compression the rest doesn’t matter. Your shop should know that. Rebuild the topend your self. It’s not that hard on the 657x motor.

 

[mikidymac]

The compression is troubling but won’t cause it to run perfect then not start then work perfect.

I would check the check valve and pressure relief on the fuel tank vent. Also try turning the fuel off every time you turn the engine off to make sure it isn’t flooding from a leaking needle.

You are going to have to address the compression though. Have you called SES?

 

[mkjj123]

SES voicemail is full so can't leave a message. Emailed him, but no response yet. Hoping he's still in business.

 

[Digdog]

When it is in the 'no' start/run mode , pull the plugs and see if it has spark. Sounds like you have a bad connection/coil/magneto. Look at the plugs and see if they are dry or wet when this happens, has it ever backfired? The compression numbers you have will still run, maybe not with full power.

 

[mkjj123]

I've confirmed spark when the issue was happening. Plugs may have been a bit wet with gas but i don't think it was actually flooded. I let things dry out and still wouldn't start. I'm fairly certain the shop went through all the electrical components and connections. Even replaced the battery with a 'good' one (i had one from AutoZone).

Anyone deal with SES recently and know if they are still in business? No reply back from them.

 

[Digdog]

I've confirmed spark when the issue was happening. Plugs may have been a bit wet with gas but i don't think it was actually flooded. I let things dry out and still wouldn't start. I'm fairly certain the shop went through all the electrical components and connections. Even replaced the battery with a 'good' one (i had one from AutoZone).

Anyone deal with SES recently and know if they are still in business? No reply back from them.

Did you try new spark plugs? I wonder if the rotary valve is out of timing?

 

[mkjj123]

Yep, the shop has gone through everything; replaced the plugs, new battery, cleaned all contacts, rebuilt carbs, confirmed pop-off, checked fuel pickups, i believe checked all the vents in the fuel system. I've spent a bunch of money for them trying to figure it out, and just want to find that smoking gun that is causing the issue. It's not a complex system but very frustrating for sure. It FEELS as thought it's not getting fuel, but the plugs are wet when the issue is happening. Fuel, air, spark - not sure what else is needed, other than compression but seems consensus above says that this wouldn't cause intermittent starting.

If rotary valve was out of timing, would this cause random non-starting? or would this be more consistent and not run well when it did start? It runs great when it starts and gets up to ~45 mph.

I greatly appreciate the suggestions. Hoping for them to keep coming and for one of them to be the solution.

 

[Digdog]

Did you try a new coil? If it's not that then the magneto might be the culprit, wet plugs points to these two items or bad plug wires or the rotary valve out of timing.

 

[etemplet]

Pick up coil. Not sure your ski has the same system but the 1996 I bought did the same thing and after much much troubleshooting and no tools.... I removed the cover and found everything full of corrosion and rust. The coil was good but covered with metal so it could not detect the firing position. After I replaced this part and cleaned the area.... the ski started just fine. Every now and again, no spark but removal and reinsertion of the key would correct that. This is what it looked like when i got it cleaned up.

 

[mkjj123]

Thanks for the suggestion. Unfortunately the shop had gone through the pickup and all electric parts. It was a bit rusty but they cleaned it up and still had the intermittent start issue. Fuel system was gone through completely. The entire thing has been gone through, actually...multiple times.

So the only thing left is compression. For a few $hundred I've told them to go for it and open it up to see if they can find the compression. If it's in the top end, they will fix it and we'll see. If it's in the bottom, that will be the end of this adventure. At this point I just want to know what the problem is.

I'll let you know the result...

And thanks again for all the great suggestions.