2011 Pro plug fouling machine.

[Murph]

In a decel situation with the throttle at an idle(or close to) position I'm not sure whether oil can be drawn through the oil pump via vacuum?

I'm not thinking vacuum, but rather the oil pump is spinning at a higher rate due to the clutches being engaged and sending more oil combined with no air (throttle plates closed), no fuel because of closed throttle. The resulting VES in combustion chamber is not lighting off and fouling plug.

As you mentioned, I have also owned Pros that looked like mosquito abatement vehicles at startup--smoked for days with no plug fouling issues. BUT that was not with VES, don't know if VES has anything to do with it.

I totally appreciate the input-- this is the worst mechanical a$$ kicking I've ever experienced....

 

[Murph]

Just some info, i run at 98 temp all the time and it doesnt foul plugs.

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This is actually really helpful.-- None of our Pro's would dip below the 100 degree threshold while riding and thermostat open. Usually they would sit around 102-5* Good to know that this can be a normal operating temp. This motor has SLP head on it so I thought maybe this was the reason that temps could be lower.

 

[Merlin]

I feel your pain.

It might be worth testing the check valves just to rule them out.

IMO, this is one of the best troubleshooting threads I've seen on S.W.

Good luck!

I'm not thinking vacuum, but rather the oil pump is spinning at a higher rate due to the clutches being engaged and sending more oil combined with no air (throttle plates closed), no fuel because of closed throttle. The resulting VES in combustion chamber is not lighting off and fouling plug.

As you mentioned, I have also owned Pros that looked like mosquito abatement vehicles at startup--smoked for days with no plug fouling issues. BUT that was not with VES, don't know if VES has anything to do with it.

I totally appreciate the input-- this is the worst mechanical a$$ kicking I've ever experienced....

 

[BILTIT]

Another thought about the check valves, if i recall correctly, i think INDY Dan has replaced them everytime on my engines when he touches them.

 

[BILTIT]

This is actually really helpful.-- None of our Pro's would dip below the 100 degree threshold while riding and thermostat open. Usually they would sit around 102-5* Good to know that this can be a normal operating temp. This motor has SLP head on it so I thought maybe this was the reason that temps could be lower.

Yes i have a PAR head and bypass tstat aswell. I also found that when i put on the powerclaw track and "standard" snowflap i saw the temps drop even more. The head seems to be common denominator with lower temps though, many have seen lower temps with it (aswell as the remote/bypass tstat).

 

[BILTIT]

Have you changed the fuel filter? I had a filter issue which caused weird things and looked like it was really rich but was actually just all the oil accumulating on the plugs. I never fouled plugs though.

 

[mitchellbrower]

did you ever figure out the problem on this??

 

[NapaMatt]

any fix to this yet?

 

[SRXSRULE]

Guys... this post was from 3 years ago. do you really think he is still working on it?

 

[NapaMatt]

no, but i wanted to know his fix

 

[MrIQR]

What was the fix???

My 17’ has the identical issue.