Wrong fuel filter – now won’t reach WOT

[Mike Schmidt]

I made the mistake of letting a friend change my on-engine fuel filters last spring as I was short on time.  He incorrectly used the FS1280 which is 20 micron vs the required 10 or less.  Well, I’ve recently been having an issue where I only reach about 2500 WOT and notice a bit of stumbling.  The running gear is clean and there don’t appear to be any leaks in the system.  I changed the filters to the correct ones and am having the same issue.   Could the wrong filter have let in particulates that clogged the injectors or something?  What should I do to troubleshoot and fix the problem?  How likely is it that this is the problem?

Topic

[Clark Leighs]

I doubt the fuel at 1.5 yrs is the cause of the problem especially when you see no water in the filters.   

How about dirt though?   Have you examined the pleated element for dirt and clogging?   

Have you taken a fuel sample and sent it to a lab as a cross check?.

Yes, I use labs.  I started at work 30 or more years ago and have carried on with my own boat and on two occasions  the testing, I believe, saved my bacon warning me of an impending problem before it became a real problem.   THey are not foolproof of course but nonetheless can be extremely helpfull.

[Mike Schmidt]

One more question before I get started, though.  My fuel is about 1.5 years old and I never put in any additives or stabilizers.  Is it likely that the fuel is bad?  I see no water in the Racor bowls.

[Mike Schmidt]

Yep, I know.  My initial question had to do with having the wrong on-engine filter installed, but now that I know that’s not the issue I’ll go through all your troubleshooting tips.  I’ll report back soon once I have some data.

[Tony Athens]

Mike,

Off course you know what you have posted will not help us much at all..   <br /><br />

“Tony’s Tips” 

Low power trouble shooting  

Until you go thru that one by  one, we are all just spinning our wheels

[Mike Schmidt]

Well… I see now that the FS1280 is the correct filter.  I guess I need to go through the diagnostic steps to figure out the cause of the lack of WOT.  I’ll start with a vacuum gauge between the engine and racor and fuel pressure gauge.  Another interesting thing is that this all seemed to become a problem right after I deleted the fuel cooler.

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