Carb trouble I think

[Longhorn21]

I took my 87 Supra Comp out today and it ran great for an hour then it started pulsating between 1000 to 2000 rpm's. If I go at idle in gear it runs great and if I'm over 2000 rpm's it fine. By pulsating i mean it will rev-up and then rev-down over and over again. I think it may have something to do with the Holley carb but not sure what. Any help would be appreciate thanks

[michael hunter]

When was the last time the carb was overhauled?

[foxriverat]

Have you checked the fuel filter? my 96 efi comp started surging. And the fuel filter was the culprit.

[Longhorn21]

I got the boat about three years ago and the previous owner said the carb was 1 year old. If the fuel filter is the screen that is hooked to the carb from the fuel line then I have checked it and it is clean. It also floods if I keep it off for long period of time, so I'm thinking that my floats are not stopping the gas after the engine is off. That doesn't explain the pulsating though

[michael hunter]

Also check the power valve. Check the fuel filter/water separator. If its go points check the point gap.

[Longhorn21]

Less then a year ago I had the timing, new distributor cap, points, wires, and a new starter. I'm guessing I need a carb rebuild

[Longhorn21]

I don't have a fuel filter on this boat only a screen at the carb. How do I check the fuel/water separator. I don't want to take the carb apart if that's not the answer. I think it has to do with the carb, but what in the carb could cause it to flood other than the floats. Sorry this may sound stupid but I am a novice and trying to learn. The pulsating or surging between 1000 & 2000 rpms only is driving me crazy what could it be

[wideopen]

Rebuild the carb and you will fix the problem. I have an 88 comp, and the exact problem has happened to me more than once. Now, I rebuild the carb about every 2 to 3 years and it works great. Pay particular attention to the jets and needles, use lots of carb cleaner, and remove the sediment you find in the float bowls--you may have to gently scrape it away. Hope this helps.

[wideopen]

Also, you should have a fuel filter/water separator on the stringer at the front of the motor, left hand side. Replace this every season. It's a canister filter--Wix part #33110. Most automotive parts stores have them. If your boat doesn't have this filter, install one. Skidim should have it.

[Longhorn21]

That's Wideopen for the reply. When you talk about rebuillding the carb are you saying to get a kit or just open it up and clean everything with carb cleaner. I can open it up and clean it with carb cleaner, but getting a rebuild kit may be alittle hard for somebody like me that's never done it, but I would try If that's what your talking about.With the fuel/water separator are you saying to replace the filter or the whole unit. Sorry if these are stupid questions