OMC 4.3l

[Lifter]

Hello , I know I don't post much, and now the time I post I
need something.
I have a 4.3 l v6 motor and at 3500 rpm (about 30 -35 mph) runs great
but when I throtle up to 4000 rpm (about 38-40 mph)there is a serious loss of power any ideas?
I thought it was the fuel filter but the problem still exists
It seems like it is starving for fuel but now i'm not sure

thanx for any imput

 

[Last Chance]

IF it is a nice smooth power loss, fuel is usually it. Check the pickup screen on your fuel tank, if it is not easy to get at, fire compressed air DOWN your fuel pickup with the fill cap for your fuel tank off. Thank will rule out the pickup screen.

 

[wolf]

could also be a weak fuel pump, or metering rods,many things timing?how old are the plugs,wires etc start with the cheap stuff it may be time consuming but you will get it.

good luck wolf

 

[Degree of Freedom]

Along similar lines...my 3.0L mercruiser has developed a short hesitation when I drop the hammer. Not a problem for fishing, but kinda sucks pulling a skiier out of the hole...

Similar causes?

 

[scott craven]

Try and run a can of seafoam through the motor.
my buddy had same problem, and he spent a long time dicking
around changing plugs,thermostat various other stuff
He ran the seafoam through and no more hesitation,
motor runs like new !

 

[Degree of Freedom]

Thanks, I'll give that a try...gotta love the simple fix.

 

[Lifter]

where would a guy get seafoam on the lower mainland

 

[Lifter]

tried the compressed air and seafoam problem still exists
any more ideas would really like to get on the water
and not worry about the problem

 

[JimmyJames0363]

I'm having similar problems and with many hours of research I found that there is a brass fuel filter inside the carb itself. I took out that filter and put an inline see through fuel filter in place of it. I’m still having low pressure problems but it’s a thought for you. I wasn’t sure if this was the fuel filter you changed or not but thought I would let you know..

 

[wolf]

My buddy had the same proplem with his 350 and it was the fuel pump so you may want to look at replacing that his was regestering at 6 lbs on start up then 1 lb on running put a new one in now it goes like (well you know) and sounds like a new engine.

Good luck Wolf

 

[Mongoose]

quote:Originally posted by ebbtide

where would a guy get seafoam on the lower mainland

all of napa auto parts sells it

 

[Lifter]

i replaced the fuel line
seems it had a pin hole in it
runs as new

 

[daddystoy]

Like Jimmy James I to have a small inline brass fuel filter. It is located in the fuel line adaptor fitting. Maybe it's the same carb? 2 barrel holley on a 302. For years I never had a problem with this filter, always changed and/or drained the racor filter. This year at one point the boat wouldn't even want to idle. Took this brass filter out, cleaned it, everything seemed to run fine. Was out again and had slight hesitation at high throttle. This time took it right out and left it out. No problem with hesitation. Seems to be the problem. I will look for a new filter to replace this small brass one.