Holly 600 CPM problem - HELP !

[Donzigo]

I have a curious problem. The engines are running at 3,400 RPM, cruising fine, then the port engine suddenly just stops running. It doesn't always completely stop, sometimes it just slows to a low RPM. I bring the boat off plane, and it's running. I speed up again, back on the step, and sometimes it will hold fine and other times it will stop again.
Boat: Z-33 - twin 454's - 1996 models (Gen 4, my guess), with Holly 600 CPM carbs.
My thoughts: 2 monthes ago, I just changed the distributor light part that produces spark. (sorry, forgot the name). The enignes were for sure needing them. They were rusted. Ok, that was 20 hours ago and everything was fine; so, I don;t think that is the problem. I think it's the power vavle on my Holley again. it seems I re-build these carbs once a year. I thinks it's time to do it again. Can I do that myself? I do everything else, just never re-built a Holley. I've done Rochesters and Carters. Will I be surprised with anything difficult on a Holley? Part? Where can I buy them?
Any ideas?..............thanks for your comments.

[MOP]

Rich they are no worse then any other to do over, find out what needs to be done to update the power valves. The new one don't go bad if the engine cough's, through the carb Jim can get you straight on this one.

Phil

[BUIZILLA]

Richard, your symptoms don't seem to be PV related.

JH

[Donzigo]

MOP - Buizilla,

Thanks for the reply. I called my mechanic pal this morning and he said the same thing. If the power valve pukes, it goes bad, period. My engines have electrical fuel pumps on them. He suggested that perhaps the fuel pump might be bad since they go bad gradually. I'm going to switch sides this morning and see if the problem follows the pump. He also said to disconnect the Hobbs oil pressure switch and run it without that, if need be.

Off to the dock do the work...............to be continued

[mrfixxall]

I have a curious problem. The engines are running at 3,400 RPM, cruising fine, then the port engine suddenly just stops running. It doesn't always completely stop, sometimes it just slows to a low RPM. I bring the boat off plane, and it's running. I speed up again, back on the step, and sometimes it will hold fine and other times it will stop again.
Boat: Z-33 - twin 454's - 1996 models (Gen 4, my guess), with Holly 600 CPM carbs.
My thoughts: 2 monthes ago, I just changed the distributor light part that produces spark. (sorry, forgot the name). The enignes were for sure needing them. They were rusted. Ok, that was 20 hours ago and everything was fine; so, I don;t think that is the problem. I think it's the power vavle on my Holley again. it seems I re-build these carbs once a year. I thinks it's time to do it again. Can I do that myself? I do everything else, just never re-built a Holley. I've done Rochesters and Carters. Will I be surprised with anything difficult on a Holley? Part? Where can I buy them?
Any ideas?..............thanks for your comments.

I had the same problem with a cust boat,it was the fuel filter in the fuel inlet of the carb. My cust boat felt like it was running out of gas,i came to a idle then it would fill the float bowls and run fine till the float bowls drained and start running like crap again...

Try this run your boat.when it starts running like crap shut off engines and pull the brass plug out ot the float bowl (its above the accelator pump) and see if theirs no fuel in the float bowl...
good luck

MD

[tmdog]

Same problem, was the elec. fuel pump. Any case it sounds fuel related as Mrfix says.

[Donzified]

Do you need the power valve?
I bought a plug for my 650 cfm on an 18 with a 350
after a few replacments.
It seams a power valve would better fit an auto application.

[Cuda]

I don't think it's the pv either. I've been hunting a similar problem on my Formula for a while now. If the pv blows, it should run rich all the time, not starve for gas. Check fuel filter/ water separator, fuel lines for pinches or kinks etc. Btw, im my opinion, Holleys are by far the easiest of all carbs to rebuild. As MOP said, they have a new system that prevents the pv from blowing out everytime the engine sneezes. Good luck, let us know when you fix it.

[Donzigo]

Thanks to all for the comments.

I disconnected the Hobbs Oil pressure switch - still got the problem

Drained fuel separator - no problem there

Switched fuel pumps - Still got a problem on the port side

Took the Holley off - That's got to be the problem. Either rebuilding it myself or drop it off to the guys who did it the last time......... $125 to boil it, rebuild it, and paint it. We'll see how my time goes this week. Probably just drop it off.

I can't think of anything else....................

[Cuda]

Richard, I've used Superior Carburetor before. Much cheaper than Pinellas Carburetor.

Superior Carburetor Svc
Address: 11005 49th St N, Clearwater, FL 33762
Phone: (727) 572-7755

[MOP]

Rich don't rule out that tank pickup I know both are running out of the new tank, that may fool you into thinking no way can't be supply one engine is running great! T in a vacuum gauge between the tank and the engine see what you have at speed under load. You may have sucked a little crap into the pickup or anti syphon valve. Finding flakes of aluminum and drill shards in anti syphon valves is common, they end up sticking part way open.

Phil

[BillG]

Try taking the bronze filter out of the fuel line at the carb. It may look like it is clean, but try it without the filter.

Bill G

[Donzigo]

Late last night, I got to thinking about it, I thought about that filter too. I think it's best to just rebuild the thing and take that out of the equation. I seem to have to rebuild it every year anyway.