Any marine techs online??

Question

i am going back to the shop after vacation. My service manager says we have a four winns w/ 5.8 Ford in it. From what the customer told him was that on calm water boat runs up nice, but in a chop engine cuts on and off above 2500rpm. I believe he said he changed the water seperating fuel filter, and now even in calm water only able to turn 2500rpm. My first approach is to change out the filter again, then apply a shop tank with known good fuel see if the problem goes away look into a fuel vaccume and pressure tests. My second item to look into is ignition I was thinking to hook up a timing light to see if spark is present during the failure. Any other suggestions to help save some time? t/y

Answer 1

Sounds to me like an electrical problem.  Something, somewhere is failing in choppy conditions.  Could be a simple loose or corroded connection, a faulty kill switch, even a cracked spark plug or wire grounding itself out.

Answer 2

I think you are on the right track with the fuel.

Maybe a cracked fuel line?

Close to the water seperator?

Answer 3

As redundant as this may sound, check your "kill switch." That's the little red lanyard that attaches to the kill button via a little plastic clip. One of my customers had a Four Winns that did the exact same thing. It took me forever to figure it out, too (I shouldn't say that, but it is true). I went through fuel pumps, carb rebuilds, etc. and then when it happened, I'd check for spark and there was nothing there! Checked the kill switch, there it was. If it's the kill switch, replace it and call it good. Other than that, check for water in your fuel. With it randomly cutting out like that, I highly doubt (if it is a sudden shutdown, meaning that the engine doesn't bog or surge before it does it) that it is anything to do with your carb with the exception of your manual fuel pump/accelerator pumps. Good Luck!

Answer 4

make sure any wires   especially ground wires pertaining to the distributor and any ignition modules or computers  are clean just because they look clean does't mean they are the best clue is green oxidation around any connections.

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Answer 5

I had a similer problem on my four winns...what they found was plugwires grounding out on block

Answer 6

Ahh, geez, I remember this problem from my school way.  We were talking about this one day in class, and the subject was just that, a sterndrive, at least I think it was, cutting out in choppy water but ok in calm.  Ummm, It does sound like an electrical problem, but could also be fuel related.  Did you check for the heck of it the fuel pump?  If the diaphragms are ruptured, fuel will go through the sight tube at the carb and flood it out, causing it to die.  But umm, yeah, possible a stop circuit issue.  Disconnect MOC-Means of Control.  Take that away and see if you have  a running issue.  Of course use your own fuel source.  I'm having some issues at my work too with some boats.  Once in a while I get a few that stump me.  Sorry, hope I can help.  But yea, go back to your basics...visual, spark, compression, fuel, and whatever the fifth test you like.

Answer 7

air cleaner and carb bowl.