Blaster help. cant work out this running problem

[doorslammer]

hey all, i have been chasing this problem in my blaster for weeks. and im ready to burn it. i dont know what else to try.
its a basic set-up, jetmanic ported cyl, twin 38's, limited b-pipe, ada girdled head (190PSI in each pot).

heres the problem. put the ski in the water and it runs great, really well no problems. then it will lose power up top, feel like its missing or dropped a cylinder, as of late it just gets worse and worse untill it stuggles to pull me onto the plane. buy this time i usually pull up onto the beach and either tweak the carbs, check or change the plugs (front plug comes out dark brown rear comes out whiteish?) , try anthing to work this thing out. put it back into the water and it runs great for a bit, but not for long. sometimes while riding it will find itself and run great for a bit, then go back to its sad powerless state

heres what ive done.
-first the start stop switch started to act funny, pulled it apart and it looked like crap so i replaced it
-new kawasaki coil (recently forund one of the ht lead had a break and fixed that but no change)
-checked the stator and found the lighting coil had come apart and had gone throught the everything, got a s/h stator that checks out on all ohms tests and put it back together
-rebuilt the carbs, 2.0 n/s 80g spring (20psi popoff) 140main, 75 pilot, 3/4 out on the mains and 1 1/4 out on the lows (runs great when it runs)
-pulled the reeds (standard stainless reeds) look good and all but 2 pedals are sealing well (could 2 pedals cause this, im a bit skeptiacl about continuing to throw money at things that are not helping)

so last time i had it on the trailer to tune it. run great, could have it running under load @wot with no hesitations or missing , put it on the water and it runs great for a while then gets worse, could the bouncing and jarring from the water cause the cdi to get worse, does ths sound like a cdi problem?
i have also sprayed a heap of brakeclean arount the base and rear seal and it doesnt seem to affect idle.

i have a few ideas but dont want to waste money, especially when i cant just swap parts.
1 the cdi is bad, ive tried checking this with a multimeter as per yamaha manual but i get no reading from any comination of wires, thinking my mulitmeter may not be sensitive enough?
2 when i had the stator out the flywheel didnt lookm that great, the magnets were not shiney and some areas had some lumps in them. also with the engine running i only get 12.8v charging at the battery, not real great maybe the magnets are bad or the reg/rectifier is gone.
3 air leak. but it runs good sometimes an then gets worse. can a airleak cause this?
4 ??

ive just about had enough of this thing. hopefully someone can help or give me some ideas, something to check.


cheers Toby

 

[Crab]

Try another stator, then cdi

 

[Byeai]

air leak can cause it

Sent from my SAMSUNG-SGH-I727 using Tapatalk 2

 

[TheBuzzard]

i didnt read you page of stuff but did you look at the internal carb filters on the pulse side of the carbs or maybe the inline fuel filter. if you have a primer pump, when it starts to bog out, pump the primer. if it comes alive, its fuel related and starving for fuel. i'd bet money thats what it is

 

[doorslammer]

im going to rig up some way of leak down testng it, anyone got a good link to doing it? im going to do a search now.

im trying to avoid just buying parts, i've already replaced the stator @ $180 and am not real keen on spending money on a another one or cdi if it might not change anything. although i know it might get to this stage as i have no other way of testing these parts and sometimes it just doesnt work even tho it checks out :banghead:

i pulled the little screens (clean) from the carbs just before the last ride when i reset the carbs, (went from a 1.5 n/s to 2.0). pumping the primer does nothing, it just bogs right down then goes back to its rough running. i also ran a line straight from the reserve pickup to the inlet of the carb, bypassing the filter and tap ect, and still no better

 

[donteatdirt]

If your spark plug is coming out "white" check the gasket on the exhaust mani, might be leaking water back into the cylinder. oil and water will make a milk looking white. Also cut back your plug wires and put some msd boots on. Stock wires an boots suck and can cause wired problems @ hi rpms. both can be done yourself for under $50.

 

[tipiwakan]

I had exactly what you are describing happen to my superjet. Next time it does it open the gas cap.If you here a vacuum sound your tank vent is plugged. I fixed my vent and it never did it again.

 

[grahammy]

Exhaust leak will do that, every time you stop and take hood off, the engine bay gets clean air

 

[todc207]

I had a very similar issue and after chasing it for a month is was my MSD Enhanser ignition. I swapped in a different one and it ran perfect so I replaced it. Not sure if you have one or not but I would check that. Also the plugged gas tank vent a few posts up is a common problem as well.

 

[Nemo]

I'm with Crab, electrical. They warm up and can do some crazy things. Swap parts if you can and take the electrical completely out of the mix. The exhaust leak and fuel tank tests wont hurt and are easy to check. The plugs are a good clue.

 

[wanderer1]

Rear plug is white? Is it milky white or dry white? Going lean? Pull the head and check you cylinder for scoring. Not sure how an electrical issue would cause the rear cylinder to go lean, I could be wrong but I would say you have a fuel delivery issue or sucking air somewhere. Are your carbs getting there own fuel feed, or slave setup?

 

[Waveblaster785]

As stated before this is electrical. Air leaks and carb issues don't generally "reset" themselves.

 

[doorslammer]

Allready has msd boots.

Rear plug comes out dry white, like its lean. But I didn't think an airleak would come good. This or the fact it's starving for fuel. I will check the breather when I get home from work.
Carbs are a standard 38 set-up. So slave. Fuel from tank, to tap, to filter, to rear carb (with pump) to front carb, then back to tank

I always thought it was electrical except for the white plug, I'm going to try get a couple of those rubber expandable core plugs and do a leak down this week. What size is the std b-pipe manifold to mid pipe?

cheers for the ideas and suggestions so far

 

[Nuklear6]

Alot of good info above. The check valve in the fuel tank vent does plug sometimes or possibly it was put in backwards? But dont forget there should be some positive pressure in the tank when you crack the cap after riding, and its so hard to tell if the phishhhhh sound is positive pressure or vacuum. So rather then worry about listening to that, just go right to the vent line and check valve to check it. Should let air in but not out...

On the electrical side i would give great attention to the over heat sensor (if you still have one) or the wires that used to be connected to the sensor. If you do not have the sensor and the wires are not capped properly anytime the pink wire gets a ground it will go into limp mode like the ski is over heating. It is possible for the pink wire to even get a ground through moisture in or around the wire end or lead (more so in salt water). Not saying the above is your problem just giving a few more things to check.

When you get her running right again get your carbs pop off pressure back up to 40ish+ psi. With dual oem 38's there is no reason to run he pop off in the 20's.....

And pictures of the plugs would help us help you.

 

[JetManiac]

Alot of good info above. The check valve in the fuel tank vent does plug sometimes or possibly it was put in backwards? But dont forget there should be some positive pressure in the tank when you crack the cap after riding, and its so hard to tell if the phishhhhh sound is positive pressure or vacuum. So rather then worry about listening to that, just go right to the vent line and check valve to check it. Should let air in but not out...

On the electrical side i would give great attention to the over heat sensor (if you still have one) or the wires that used to be connected to the sensor. If you do not have the sensor and the wires are not capped properly anytime the pink wire gets a ground it will go into limp mode like the ski is over heating. It is possible for the pink wire to even get a ground through moisture in or around the wire end or lead (more so in salt water). Not saying the above is your problem just giving a few more things to check.

When you get her running right again get your carbs pop off pressure back up to 40ish+ psi. With dual oem 38's there is no reason to run he pop off in the 20's.....

And pictures of the plugs would help us help you.

X2 on the above in yellow.

Is this problem in fresh or saltwater? What cdi are you running?

It sure sounds like a going bad stator charge coil that works and ohms good when cold and then going bad when hot. However, different readings on plugs seems like a coil wire/cap issue in saltwater when wet.

 

[doorslammer]

checked the tank vent and 1 way valve and its all good and the one way is the right way.
i thought about the temp sensor but its doesnt feel as thought its dropping to a consistant rev limit. sometimes it wont rev much at all, other times it still goes allright.

have got the standard cdi and its in saltwater.

i have a complete 61x ignition system here from another blaster but that ski doesnt run and i have never seen it run so im not sure if i will just be adding other problems.
can i use a 61x stator and flywheel with a 62t cdi? im may just swap these over and if it doesnt change ill wack the 61x cdi in as well while im out on the water... whats the worst that can happen? it runs good again:lmao:

 

[doorslammer]

Plugs bit hard to tell. I had it idling on the trailer for a while after I got home. But one plug is a bit more white on the porcelain and usually the earth strap is whitish as well. I will take a pic of them next time I go out if I haven't found a solution to the problem

 

[Crab]

Like said before, get rid of that sensor.

 

[doorslammer]

should have been more clear, sensor is disconnected and the bullet plugs (pink and black) on the cdi are capped with the rubber sections off the old wires and its all sealed inside the ebox. doesnt seem to be any moisture or salt in the ebox either

 

[Crab]

My suspisions are still faulty pickup, and if not then cdi. Does it still act up in fresh water? I have seen a broken wire that you couldn't see also, only replace with known good parts or your chasing your tail.