3.0L high rpm stalling...

[copelandcf]

After numerous problems with my 89 Chris Craft w/ 3.0L merc I'm finally getting close to getting ready for the water again. The dwell, timing, and idle are set correctly. Everything runs fine until about 2500rpm's, at this point it starts to lose power, and if pushed further will stall. I never had this problem before now, it was always rough idle, etc... Pulled the plugs and looked like it was rich??? I looked into the carb and it seems only one of the bowls is wet, the other is bone dry. My guess is clogged carb. I checked the filter by the carb and it was pretty dirty, sand and maybe some resin chips. I cleaned the tank thoroughly before but maybe some resin was in the carb or lines or pickup.

Gonna check the fuel pump filter tomorrow to see how dirty it is. I dont think its the pump because ran well at high rpm before tune. I've read it could be the anti-siphon valve, but what is this and how do you test it? Also does this engine have a fuel-water seperator?? Compression is good. I also read changing the coil might help. I bought a car one a while back when I was having ignition problems, but swapped back to oem when issue remained after coil swap. Coil looks identical, should it work ok? Any way to test the old coil with multireader?

Seem like on the right track here? Thought I would ask before blowing more money on parts I dont need.

Thanks for the help!!

 

[chiefalen]

Re: 3.0L high rpm stalling...

So you got the filter in the fitting bye the carb clean?

And your gonna get the one in the fuel pump if it has one clean.

And if you follow the hose back from the fuel pump does it go to a canister looking device that has a filter on it that looks like a oil filter.

Or the hose will go to the fuel tank.

If it goes straight to the fuel tank the hose from the fuel filter you have no fuel water separator.

Ok where the hose enters the fuel tank is a fitting that is the anti-syphin valve.

Unscrew it from the tank.

You will need to take the hose off it.

Blow thru it from the bottom does it open the ball.

There is a fuel pickup tube connected to that fitting on the end that goes in the tank should have a screen on it, it clean?

Now at this point you can suck all the gunk out of the tank.

And heres how.

Raise the bow of the boat, stick a clear hose down in the tank and into the back corner, and hook the hose to a cheap electric fuel pump from any auto store, and hook a piece clear hose on the other side of the electric fuel pump.

Suck all the garbage out of the tank into a clear bottle till you see clear fuel entering the container and stop.

Put the fuel pickup, and anti-syphin fuel hose, back together like you found it.

Ok take off and clean the carb.

Hook back the carb and post how it runs then.

Oh while at the store buy a cheap gauge and check the fuel pump that it gives you 4-6 psi.

Maybe it is the fuel pump and you can always use that gauge to test your out drive for leaks.

Good luck.