94 SPX Not Firing

[JeffG]

Ski sat for over three years before I got it. i started with draining old fuel, putting in new plugs. I have spark, but it doesn’t start (or even try). Decided to pull the carbs and rotary cover. Rotary valve was dead on, carbs are all Mikuni parts and look clean. Put it back together and still nothing. Poured some premix in the carb to see if it would fire, still nothing. Ski ran before sitting and now it won’t even attempt to fire. Battery is good and it cranks very easily. What am I missing?

 

[Ckrawiec]

Have you tested the compression of the cylinders? Don't use a Harbor Freight guage....borrow one from an auto parts store.

Have you poured a little pre-mix directly into the spark holes and then tried to fire it?

 

[JeffG]

Have you tested the compression of the cylinders? Don't use a Harbor Freight guage....borrow one from an auto parts store.

Have you poured a little pre-mix directly into the spark holes and then tried to fire it?

I have not tried pre-mix directly into the spark holes, I will try that tonight.
I will also rent a compression tester again to verify, but it had good compression before it sat. Would low compression cause it to not fire at all though? This is on a trailer, not in water.

 

[Ckrawiec]

I have not tried pre-mix directly into the spark holes, I will try that tonight.
I will also rent a compression tester again to verify, but it had good compression before it sat. Would low compression cause it to not fire at all though? This is on a trailer, not in water.

Yes, low compression could potentially cause it not to want to fire up, even on a trailer. 150 psi is ideal, 130 is marginal, 120 is indicative of a top end rebuild at a MIN usually....so always double check the compression, preferably with 2 good guages (if you can). Compression should be within a couple psi or the same between cylinders.

But, all that said.....you stated you have Spark, so a little pre-mix in the cylinders SHOULD get the engine to at least start to cough and try to start......even for a brief moment......IF you keep getting nothing....then we will need to dig deeper. Spark + fuel + compression = explosion.....so it should want to start

 

[JeffG]

Spark + fuel + compression = explosion.....so it should want to start

This is where I'm at, and confused why I'm getting nothing. New fuel and new plugs (tested plugs and I can see spark). Can't fathom why I'm getting nothing at all.

 

[Ckrawiec]

Yeah, that's a head scratcher......when all else fails, we start from the beginning:
1) did I re-connect everything properly? (I've personally forgotten to put the Pulse line back to the carb so I was getting no fuel), 2) try running an aux fuel bottle directly into the carb fuel inlet (bypass the ski fuel system) 3) are my carb internal fuel filters squeeky clean 4) are my carb needles (Low & High) set properly 5) are all my electric connections good, clean, bright and tight.....

Just some things to double check...no costs but time.....it's usually always something simple, but frustrating!

 

[JeffG]

Just some things to double check...no costs but time.....it's usually always something simple, but frustrating!

I hope it's something simple, I'm getting the "if you spend any more time on this..." look from the wife and it may end up having to go cheap soon lol..

 

[Ckrawiec]

I hope it's something simple, I'm getting the "if you spend any more time on this..." look from the wife and it may end up having to go cheap soon lol..

I KNOW that look!.....they just don't get it, some things take a little (or a LOT) time
Jeesh....what does she EXPECT from a 26 year old ski.....does SHE run as well now as SHE did 26 years ago......huh? - ASK HER THAT......NO DON'T....just kidding!