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Problem with Older V6 High RPM

ri_popper

New member
Well I've got a typically

Well I've got a typically great running 1987 Excell XH 2.6 liter v6 Yamaha. I took it out a couple weeks ago and on the way in I started having a problem with it. When I tried to get to High RPM (over 4200) it would start to bog down. I changed all my fuel filters and spark plugs took it back out and it kept doing the same thing Low RPM sounds find but when I punch the throttle it flattens out and sounds like it's having a problem getting fuel over 4000 to 4200 RPM. I did have one bad coild which I replaced but that wasn't the problem either. I'm thinking maybe fuel pump??? any ideas out there?

Thanks very much
Armand
 
take a look at the plugs and s

take a look at the plugs and see if they are all the same in colour or if you have one looking oil/wetter looking. This will help pin it down to a cylinder to concentrate on for fuel or spark
 
"Thanks Profisher, I pulled th

"Thanks Profisher, I pulled the plugs and that's how I found out about the bad coil. Had one plug that was clean and looked like now it wasn't getting spark. I replaced that coil and I'm doing the fuel pumps just to be safe.
I'll post up results."
 
Well I rebuilt the carbs and t

Well I rebuilt the carbs and that wasn't the problem. Changed the fuel lines that wasn't the problem. It ended up being the fuel pumps I believe

Armand
 
"I have a 99 carbed Vmax 150 a

"I have a 99 carbed Vmax 150 and had the same issues. Found ground loose on coil first time that corrected the problem. Second issue was same as yours, would not exceed 4900rpm. I changed the plugs, installed two new fuel pumps and cleaned the fuel filter, did not correct. Poured in a bottle of STP octane boster and corrected the issue. I have had to do this twice so I think I had some bad gas."
 
James thank you very much for

James thank you very much for the feedback. I'm gonna try to get the boat out soon and find out if I've got it taken care of. I'll throw some octain boost in to help it out.

Armand
 
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