Coil question

[ub6ib9]

I'm trying to troubleshoot a 92 sj that wasn't running last year, it was running but poorly, electrical checks as follows

Charge coil spec 365ohm +- 36.5 I have 381
Pulsar coil spec 14ohms +- 1.4 I have 17ohm
Lighting coil 0.9ohm +-.09 I have 1ohm

Do you think the Pulsar being out by 1.5ohm could likely be culprit? I checked rectifier and cdi they are in spec, I don't want to remove block if I don't have to, Im going to look into fuel supply next

Thanks

 

[Harbor]

Have you done a compression test yet ?

 

[ub6ib9]

Have you done a compression test yet ?

Yeah I did all the main things that's why I'm suspecting electrical, carb was thoroughly soaked and cleaned, all new internals, new few lines, filter, gaskets on everything, it had spark the last time I tried running it last summer but from what I remember the spark did not look very strong, if cdi and rectifier are good I don't know what else that leaves

 

[john zigler]

Without really hearing your ski run in person it is hard for me to say what is wrong... I will say this;

I have had ALL components test good, but actually be a problem in the past.

Yamaha Ignition coils, (Especially the old ones) are known to be weak.

I have had Stator coils, and Rectifiers cause a "limp mode" type scenario where the rev limiter in the CDI kicks in early. Engine runs on one cyl.

Same with CDI. I have had them just go bad, and rev limit kicks in early.

Fortunately I am lucky enough to have lots of used Yamaha Ignition components here, and have found it easier to just swap parts out quick for testing/diagnosis.

Not to say - you could STILL have a fuel related issue. Bad reeds, leaking crank seals, even a fuel select switch can cause issues.

 

[ub6ib9]

I did a leak down test on it at the end of summer last year which passed, when I first got this machine I had Jet send me a whole bunch of parts I took everything apart, new gaskets on everything, new starter new carb kit, made sure the jets were correct etc etc, the problem is the both low and high end ran poopty regardless of what the needles were set at, all the fuel lines were replaced, selector removed, pickups checked, but I specifically remember the spark looking dull when checking it. I have a spark gap tester I didn't have before, do you know what I should expect to see on it for you distance?

 

[john zigler]

I did a leak down test on it at the end of summer last year which passed, when I first got this machine I had Jet send me a whole bunch of parts I took everything apart, new gaskets on everything, new starter new carb kit, made sure the jets were correct etc etc, the problem is the both low and high end ran poopty regardless of what the needles were set at, all the fuel lines were replaced, selector removed, pickups checked, but I specifically remember the spark looking dull when checking it. I have a spark gap tester I didn't have before, do you know what I should expect to see on it for you distance?

Set your plug gap tight. Try .020 SPark testers I use here, have little bulbs in them that glow. I like to test with these at dusk (Sun going down) with the ski strapped on the trailer, running with the hood off. You can then easily see weak, or lost spark.

 

[ub6ib9]

Set your plug gap tight. Try .020 SPark testers I use here, have little bulbs in them that glow. I like to test with these at dusk (Sun going down) with the ski strapped on the trailer, running with the hood off. You can then easily see weak, or lost spark.

i do have one of those neon spark testers as well, but i was talking about this tool, it shows you have strong of a spark you have to be able to bridge larger gaps, those neon testers show you have spark but its not really indicative of how strong it is per say

 

[orangefinger]

why is this an electrical problem ?

did u cut coils back, check boot and replace the plugs ?

SS Switch good ? Aftermarket CDI ?

 

[ub6ib9]

its an electrical problem because i have weak spark and it doesnt run great? why wouldnt this be an electrical problem

stock cdi, all the switches are good, boots and plug wires are all brand new, new plugs

 

[ub6ib9]

I put a spare cdi in and I know have very strong and bright spark, I had it running in the shop within a few seconds which I couldn't do at all last year so that is issue one solved.

Now while the ski was running I checked the voltage at the battery and I was only at 11.5v.

Checked resistance on the rectifier and it is definitely nowhere near spec, way out. My stator checks all ohm out correctly but between the 2 green lighting wires and I'm getting 20-30 volts ac depending on rpms while running. So I'm gonna assume that my rectifier is faulty and not charging the battery and my stator is ok?

I live in Canada so ship time and ship cost is significant so anything I need to order from jet I'd like to get it all on a single order so I just want to be sure. Thanks

 

[Harbor]

I put a spare cdi in and I know have very strong and bright spark, I had it running in the shop within a few seconds which I couldn't do at all last year so that is issue one solved.

Now while the ski was running I checked the voltage at the battery and I was only at 11.5v.

Checked resistance on the rectifier and it is definitely nowhere near spec, way out. My stator checks all ohm out correctly but between the 2 green lighting wires and I'm getting 20-30 volts ac depending on rpms while running. So I'm gonna assume that my rectifier is faulty and not charging the battery and my stator is ok?

I live in Canada so ship time and ship cost is significant so anything I need to order from jet I'd like to get it all on a single order so I just want to be sure. Thanks

I chased my tail fir bit trying to test charging voltage on a work stand after a short run and not on the water hose.. On a ski I just put an enhancer in that had no prior charging issue.. I was just verifying I had everything correctly hooked up... well

It was only like .2 above open battery voltage..
Battery was at 12.2 say.., and I only saw 12.4 running.. was expecting 13 plus.. seen it before on my other ski but was running on water for quite awhile..

I’d suggest checking your bettery voltage first.. then run it on hose for awhile then some more and see what the charging voltage does..

 

[mikidymac]

These typically will not charge at idle rpm. You need to get the rpm up to about 4,000 before you are going to see the battery voltage come up.

 

[Harbor]

These typically will not charge at idle rpm. You need to get the rpm up to about 4,000 before you are going to see the battery voltage come up.

Good point

But I spun mine up to 4K and didn’t see it either.. suspecting it was Because I couldn’t run long enough and at that speed cause it wasn’t on water hose.....

 

[mikidymac]

I don't have a lot of experience testing the Yamaha's but a lot on the Seadoo's as the voltage regulators are a pretty common problem. On those as soon as you hit 4,000-4,500 you will see the voltage go up to about 13.5V.

 

[ub6ib9]

at crank the lighting circuit only put out around 4 volts AC, when i started it and revved the motor i was hitting between 20-35volts ac ** so i know that is working correctly

but even at high rpm i still only had around 11-12v at my battery

 

[john zigler]

You should see a rise at your battery, but you do need to revit it up.

Sounds like you have a bad rectifier. Not uncommon.