Fuel restriction. 3" Hg at idle. Too high?

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iammarcuse

Petty Officer 2nd Class
Joined
Oct 15, 2007
Messages
131
Hi, I posted previously about a surging problem on my 1990 2.6L 225 ETLD. http://forums.iboats.com/showthread.php?t=355556
It seems from the comments I was receiving I was tracking down a fuel restriction problem. I rebuilt the fuel pumps and saw no change in the symptoms. I did find this great thread on testing your fuel pumps. http://forums.iboats.com/showthread.php?t=283363 Mine seem to be plenty strong as they will draw a 6" Hg vacuum at idle with the fuel line clamped off.
After searching numerous posts I suspected the 'fuel feed assembly' which is a check valve between the filter and the lift pumps. Testing the fuel pressure at idle gave me almost 3" Hg with the valve in but barely 1" Hg without the valve. Is 3" too high at idle? Could it be causing a fuel restriction at higher rpms?
I will of course water test but I have to take it out of winter storage and so I want to make sure I am on the right track here before I do.
Thanks for any insight.
 
R

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: Fuel restriction. 3" Hg at idle. Too high?

on 2 strokes 2.6L and below the spec is 4"Hg at wot and 6" at WOT for 3.1 and 3.3l.
3" at idle is most likly way to much.
 
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iammarcuse

Petty Officer 2nd Class
Joined
Oct 15, 2007
Messages
131
Re: Fuel restriction. 3" Hg at idle. Too high?

Thanks. I pulled it out of storage and headed to the river. I was sure it was going to be the valve. No luck, same. BTW without the valve it pulls 1"Hg at WOT.
Back in the shop I pulled the carbs to clean. The needle seat in the carb that feeds #3 was maybe 2/3 clogged. That has got to be it! There is no way it could have been getting enough fuel. The spark plug was much lighter than the others indiicating it was running lean. I'll keep you posted. Might be a while before I can get on the water again though.
 
I

iammarcuse

Petty Officer 2nd Class
Joined
Oct 15, 2007
Messages
131
Re: Fuel restriction. 3" Hg at idle. Too high?

Problem solved! It was the plugged passageway in the carb. Ran right up to 6000 RPM and pushed the Checkmate to just under 70 MPH. Thanks for your help guys!
 
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