Problem with HP575
 

Last weekend, while running in a poker run one of my 575's started backfiring and missing above 4500 rpm. The next day it ran perfect. Anyone have any experience or suggestions regarding this problem? Thanks....

Obstruction in the fuel line?

I have 30 hours on mine and no proplems like that.

Wet distributor? :confused: It would dry out overnight in the heat of the engine room.

wipe out dist cap with acohlol and try a set of plugs ,crank motor set if it has blow by out the valve cover oil filler hole ((Pray Not))
Then leak down test motor ,then pm me if you haven't found it

good luck

TTT

Guess your TTT because you've tried the stuff above ,"NOT",- try it then ask more no one can answer any closer unless they are there WTF

Cessna, I wast just looking for more suggestions. Thanks to Von Bongo, Rippem, and Bobby for your help. I will try your suggestions this weekend and let you know how it goes!

You forgot to thank CESSNA for all of his help!!:rolleyes: :rolleyes:

Hey Craig, I think CESSNA is having a bad day!

Yea ,its my time of the month ! I just don't want those guys to get tired of postingwhen it looks like we do try what they say those guys and others help alot vonbongo's helped me before
I'm no help I enjoy reading this stuff to help my boating .
Later

maybe spark plug wire arcing against block or bracket


cardoctor

Hey Steve...
I had the same problem a couple yrs. ago while on a Poker Run in Florida. It was a fuel pump just starting to go bad. It was on again and off again and drove me nuts -- EVERYONE told me how bad it sounded. We diagnosed it and I had a new pump on in an hour. They're pretty easy to replace. Not sure if this is it, but if everything else fails, here's something else to try. Hope it helps!

scarabfan

Your original post was from a few months ago. Did anything else happen to your motor?

No, it has not had the same problem since. It was an extremely hot day, and I was running it hard in a Poker Run. The dealer said the heat probably caused a vapor lock in the fuel line. The motors have been running perfect, I have 125 hours on them. They are big-time gas guzzlers though! I would get 525's if I had to do it over! Thanks...

From what I understand the 525's work better in the warm climates. We don't have that problem often here.

As a precaution you probably should change your head gaskets. I just lost one on my starboard side. The owner of the boat before me lost a fuel pump and I think that may have damaged them.

Yes they do like gas and if they don't get enough, they get mad and break something.

There was a fuel rail recall on those motors...if they haven't been changed out that could be a contributing factor. Resonance in the fuel lines themselves could cause disruption of flow to the injectors.

I run the 575's and changed out gear ratio's to run a more efficient prop and fuel economy increased dramatically (now I stop at every OTHER gas station...)