High end stalling

[CiceroJoe]

What the heck!! Here's the problem. The boat stalls in and out when you push it at around 35-4300 RPM. And mostly when the TAPS is on level 1-2 (Slalom) I replaced the sparkplugs with some new platinum ones, and put in a new full tank of gas ( it was really low when this started) and Today i'm replacing the fuel/water separator.

Any insight. It just keeps bogging down when you crank it up. This stinks!

CiceroJoe

[CiceroJoe]

possible solutions

Guy at dealership says check the distributor electrodes for moisture, and also all my ground leads to the batteries. Also to change out the fuel filter and after that there may be an obstruction in the fuel line.

Any other ideas?

[Tige M.D.]

how about a little detail on what engine you have?

[CiceroJoe]

tige M.D. to the rescue!

Mercury Marine 350 MAG MPI V8 315 HP

[Tige M.D.]

have a fuel psi test done. should read 36 psi with the regulator disconnected.
there is an ignition trigger under the distributor cap and rotor that does strange things when they are getting ready to die.
the fuel filter has to be primed, if you change the filter and don't fill it with fuel it can give you fits.
make sure your fuel tank vent is clear.
when the taps plate is down (slalom) it is creating more drag and the engine is working harder. this leads me to believe it might be a fuel starvation problem.

[CiceroJoe]

right

I'm checking the electrodes under the distributor today. The dealer tech says if they're brownish thats the norm, but if they are greenish thats bad and moisture has gotten itself in there. I'm also going to just swap out that fuel filter, and do it just like you said this morning. When I went to the dealer to pick up a new one, he pointed out to me a junk one. When I looked at this junk one, the filter component inside was ****-eyed in there! Not fastened or pressed into place well or something, neither of us could guess but it was definitely screwed up. I'll be checking mine for the similars. If these things don't turn up a culprit i'm going to look into changing the fuel line (possible obstructions?)

BTW could I have a tech from a dealership come out and do a pressure test while it is on the lift; they are just down the street from me. Or is that something that you have to take it in for?

Thanks for the big help!

CiceroJoe

[CiceroJoe]

Fixed??

I put in the new water separator/fuel filter, and let me just say it was a pain to get out of there w/o spilling gas all over the bilge!! I also tightened down the lugs on the batteries (they were a little loose) and now it goes up to around 4900-5000 RPM without cutting out on me. It still does it when you really give it hell on the top end but its an improvement which leads me to believe I was on the right track but did not do a good enough job. Now the filter is new and there is no screwing that up, so it had to have been me tightening up the leads on the batteries. WIERD. Thats the only thing left with variable regarding todays changes I made. I still didnt look under the distributor cap at the status of those electrodes, I got rained out and couldnt do it in time but will be doing tomorrow.

Out.

[CiceroJoe]

oh yeah

Also, when I was wrapping up it ran good. I wonder if it was just burning off water in the line. I only ran it for 5 minutes.

[TeamAllen]

There might be a rev limiter above the 5000 RPM range. Maybe someone else knows a little more about that. I'm glad the lower end is fixed.

[CiceroJoe]

still doing it

Its still cutting out on power around 4800RPM. The only things left I know are the distributor cap and the fuel line possibly being clogged.

[CiceroJoe]

dang

Still does it on the top end RPM's. What the heck. Distributor cap electrodes looked normal.

Any other suggestions. I'm getting tired of all the mechanicals taking a dump on me on this boat.

HELP!

[Tige M.D.]

4800rpm is pretty close to the 5250rpm rev limiter. try running a digital tach (timing light) and check it against you analog tach.
have you damaged your prop or had any prop work done?

[CiceroJoe]

prop work

I got the boat with the wrong prop on it. Too small. So I called Tige to get the appropriate prop dimensions and then picked up a new ACME with those specs. That was last year. It ran great all year. Now, crap. I don't think its the prop but who knows.

[CiceroJoe]

I FIGURED IT OUT!!!!!!!!!!!!!!!

It was the ignition. My ignition was faulty. I knew that it was a problem but didn't think it had anything to do with the high end stalling deal. The tumbler where you put the key in there rolled over the contact points and was generally just busted in there but you could still start it if you turned the key just right. I replace it with a new ignition switch and WHALLAHH!!! Fixed two problems w/one solution. What a relief.
Problem was that when you turn up the RPMS, higher current runs through and if its shorting out in a switch, you cant get all the current you need to the sparkplugs apparently.

OUT,

CICEROJOE