CreekerMike
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Thanks miki, ill be ordering their kit shortly!
951 Fouling plugs
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CreekerMike
Active Member
Alright guys just finished up rebuilding the carbs with the OSD "Back to Stock" kit amazingly 0 left over pieces. Guess they werent kidding when they said they dont include anything you dont need. Ill be installing the carbs shortly. Ill know tommorow if this solved my issue or not!
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CreekerMike
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So i managed to get out on the water today. Started up fine, ran fine, then came WOT annnd same issue... im really at my wits end here. I was almost sure it was a fuel issue but i guess not... ill pull the raves when i get home and take a look at them. Maybe there glogged up? Any other input or suggestions would be very very apreciated!
CreekerMike
Active Member
Your right. Ill go back out in a day or two with some brand new plugs and see if theres any difference. Maybe the cleaned plugs were too weak?
CreekerMike
Active Member
Sportster-2001-951C-Stock
Well-Known Member
I rather doubt the RAVEs would work very well with the bellows disconnected like that but it amazes me you can reach 7k RPM with malfunctioning RAVEs. I know my 951 wont, it still won't quite reach 7k RPM with working RAVEs, probably the aftermarket impeller and the boat is much heavier of course..
Wonder if you're hitting the rev limiter and lights out coats your plugs with a conductive film...
Wonder if you're hitting the rev limiter and lights out coats your plugs with a conductive film...
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CreekerMike
Active Member
Is it possible the reason i was fouling plugs at WOT and stuttering was because the one rave valve wasnt opening all the way? This was creating back pressure and not allowing the engine to rev out. Therefore it was still getting fuel for 7k rpm but only achieving 5800. The unburnt fuel and oil was fouling the plugs. Right?
Sportster-2001-951C-Stock
Well-Known Member
Certainly the inoperative RAVE isn't going to help yet I'm not aware of cases where fouled plugs resulted. Since both RAVEs rely on the same pressure source, both may have not been functioning AND I agree strongly, the plugs aren't going to fare well as the cylinders aren't breathing correctly. Good chance of being wet with excess fuel, trapped exhaust gasses from lack of scavenging and what have you, can't imagine plug temps will be sufficient in those conditions to avoid being smothered.
I'll add, recovering wet fouled plugs can be sketchy b/c they will remain compromised to some degree. If it works then great but don't expect too much.
CreekerMike
Active Member
Thanks for the input Sportster! Hopefully thisl be the end of my trials and tribulations. Ill try and get on the water tommorow and report back then!
Sportster-2001-951C-Stock
Well-Known Member
Agree, at least you found something so why not assume this was the cause? It will be the 1st case I know of describing fouled plugs from inoperative RAVEs but it very well could be, it wouldn't surprise me. Anyway, a very good experience for future possible causes if this is the case.
Speaking of the devil, this reminds me I haven't cleaned my RAVEs in a couple years..... I think it's time.
Never say never, right?
Speaking of the devil, this reminds me I haven't cleaned my RAVEs in a couple years..... I think it's time.
Never say never, right?
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CreekerMike
Active Member
It didnt instantly foul the plugs every time. Sometimes it just hung around the 5800 mark and then fouled the plugs. I really think the back pressure was the issue. Ill know for sure around 430 when i drop in. Ill report back then.
CreekerMike
Active Member
Made it out to the river and im still having the same issue. Not able to achieve peak rpm. Opened it up to WOT and it started to stutter and bog down. Plugs are yet to foul. Onto the next solution. What should i look into next? Im thinking water got somewhere it shouldnt have and something is F'd up... any suggestions are apreciated!
May i add that when im out of the water i can blip the throttle and hit 7k easily.
May i add that when im out of the water i can blip the throttle and hit 7k easily.
CreekerMike
Active Member
Opened up my black ignition box and there was some water in there. About a half inch. Guessing this could definately have something to do with my issue right?
Sportster-2001-951C-Stock
Well-Known Member
One more thought on the RAVEs b/c I firmly believe in beating dead horses, call it a fetish... Were you able to confirm RAVEs are receiving crankcase pneumatic pressure from the RAVE solenoid?
There have been numerous reports of corrosion debris clogging the check valve in the pneumatic tubing. This check valve is located a couple inches from the crankcase nipple on the PTO end of the crankcase, the nipple is located beneath the carburetor.
If water has saturated your ignition coils you'll experience misfiring.
There's a ground post in this e-box where all the grounds come together under a single screw that's threaded into a plastic post. The plastic threads may be stripped and the clamping force lost, or corrosion of the terminals.
The fix for stripped plastic threads is to drill the post center through the box and use a stainless screw and nut from the outside to clamp it all back together.
There have been numerous reports of corrosion debris clogging the check valve in the pneumatic tubing. This check valve is located a couple inches from the crankcase nipple on the PTO end of the crankcase, the nipple is located beneath the carburetor.
If water has saturated your ignition coils you'll experience misfiring.
There's a ground post in this e-box where all the grounds come together under a single screw that's threaded into a plastic post. The plastic threads may be stripped and the clamping force lost, or corrosion of the terminals.
The fix for stripped plastic threads is to drill the post center through the box and use a stainless screw and nut from the outside to clamp it all back together.
CreekerMike
Active Member
Im not farmiliar with the nipple your reffering to. My rave valves bolt into a solenoid that is bracket to the hull. Right above the temp sensor. Are you reffering to the valve that the hose leaving the solenoid runs to? Ill look into that. As for the ignition box ill look into it in a bit!
CreekerMike
Active Member
It slipped past my mind. Thats the hose that has the pop in fitting right? Right down by the pulse line?
Sportster-2001-951C-Stock
Well-Known Member
This is a carbed 951, same as mine (and many others) so the RAVE systems are the same. DI 951 is much different.
Anyway yes, the fuel pump pulse nipple is forward of the RAVE pulse nipple and quite similar.
What I'm getting at is if your RAVE valves aren't receiving pneumatic air pressure they won't open. The pressure is developed from the rear pulse nipple on the crankcase, pulse travels through a one-way check valve which converts it from a bi-directional flow to positive pressure only. This pressure travels through a tube to the RAVE solenoid so when the RAVE solenoid valve is electrically actuated open by the MPEM (around 5200RPM if I recall) pressure is applied to the underside of RAVE bellows to lift them out of the exhaust ports.
If the RAVEs aren't operating, this will severely limit WOT performance.
A couple more items that will limit WOT performance is an exhaust hose that's internally delaminating, causing exhaust blockage or an expansion pipe that's being flooded with water by misconnected cooling hoses or malfunctioning waterbox valve.
Voltage regulator malfunction can cause ignition to cut out. I think removing the MPEM 15A BATT fuse temporarily will disconnect the voltage regulator.
Compromised intake reed valve(s) will limit performance.
Anyway yes, the fuel pump pulse nipple is forward of the RAVE pulse nipple and quite similar.
What I'm getting at is if your RAVE valves aren't receiving pneumatic air pressure they won't open. The pressure is developed from the rear pulse nipple on the crankcase, pulse travels through a one-way check valve which converts it from a bi-directional flow to positive pressure only. This pressure travels through a tube to the RAVE solenoid so when the RAVE solenoid valve is electrically actuated open by the MPEM (around 5200RPM if I recall) pressure is applied to the underside of RAVE bellows to lift them out of the exhaust ports.
If the RAVEs aren't operating, this will severely limit WOT performance.
A couple more items that will limit WOT performance is an exhaust hose that's internally delaminating, causing exhaust blockage or an expansion pipe that's being flooded with water by misconnected cooling hoses or malfunctioning waterbox valve.
Voltage regulator malfunction can cause ignition to cut out. I think removing the MPEM 15A BATT fuse temporarily will disconnect the voltage regulator.
Compromised intake reed valve(s) will limit performance.
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CreekerMike
Active Member
I just pulled the hose and nipple off of it and it doesnt appear to be clogged i blew very hard and i could feel the check valve pop open. Maybe it was routed poorly or kinked?
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Sportster-2001-951C-Stock
Well-Known Member
A added a couple more items above. Possibly tubing, but the tubing is pretty stout. If the RAVE solenoid itself isn't working the MPEM can't open it. A 9V battery might fit inside the solenoid connector nicely to test the function?
CreekerMike
Active Member
I can put 9v or 12v to it with some cables and a battery. Should i just hear a click? And also does polarity matter? Is a certain tab + or -?
Sportster-2001-951C-Stock
Well-Known Member
I don't believe polarity matters. The Purple/GRY wire is + though. Click should allow you to blow through I think. It might be hard to blow through, I don't remember exactly. I think mine has an LED window next to the connector so the LED wouldn't work if polarity were reversed. Try to get polarity correct, may as well.
I don'y recall if 98 has voltage regulator inside MPEM or seperate external regulator. Disconnect it for a WOT run and see if the ski runs out properly with regulator disconnected.. If MPEM has internal regulator, it can be bypassed using external type to avoid MPEM replacement.
I don'y recall if 98 has voltage regulator inside MPEM or seperate external regulator. Disconnect it for a WOT run and see if the ski runs out properly with regulator disconnected.. If MPEM has internal regulator, it can be bypassed using external type to avoid MPEM replacement.
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Sportster-2001-951C-Stock
Well-Known Member
Thinking more about your ignition coils, I doubt they're wet inside b/c if they were breaking down from moisture they probably wouldn't fire at all. Maybe it's the cause, just I doubt it a lot.
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