Running issues

[FordP33]

Ok new to me 74 Pearson 33 with what I can only believe is still the original motor. It has been maintained, some new tubing, fuel tank, carb looks newer, etc. Boat has been in Maryland most if not all its life so Ethanol fuel. She was on the hard for a year at least. Now the question. She idles like a champ, starts right up, and with smooth water runs great under load. If there is wave action power seems to fluctuate and if to rough shuts off. It really seems fuel related to me but before I start a big parts swap project does anybody have an idea of the issue.

[Administrator]

I would be suspicious of water in the bottom of the tank.

Bill

[Marian Claire]

+ 1 on Bill's post. It could also be crud in the tank being churned up due to the motion of the boat in rough weather. Especially if you have a screen/filter on the pick up tube. Welcome to the forum.
Dan
S/V Marian Claire

[capnward]

I had a similar problem. The engine was running great, but as soon as I tried motoring in serious chop it faltered and I had to go back. There must have been crud in the tank, because this tan-colored jelly was in the carb, and in the bottom of the water separator filter. Ethanol and water create that stuff. Cleaning the carb, blowing carb cleaner through the jets, and replacing the filters solved the problem. I never see that crud now, since I started running non-ethanol gas. I used to have to buy it in jerry cans from a non-ethanol gas station. Now the local gas dock sells it exclusively. I still try to avoid motoring when it's rough. Once a gas dock filled my tank with diesel by mistake, and pumped out the tank by running a separate hose down the fill hose and into the tank. I believe that may have had a beneficial effect. I don't know if there is a screen/filter on the pick-up tube, but I assume so. You say your tank is new. Make sure water isn't getting into the intake. Fill the tank before winterizing to reduce condensation, and don't keep old gas in the tank too long.

[Marty Levenson]

Where is your gas fill located?

[Sam]

Think where Marty is going is if you fuel fill on a 74 Pearson is in the cockpit [possible rain water infiltration] with tank underneath - which I think it is. similar to my 66 Morgan. Few years ago I had similar problem on an end of season bridge run after motoring in a chop. I needed to emergency dock and get a later tow [plug for Boat US] a week later. In the later spring commissioning with some valuable input from the forum the problem has and remains solved by:
- pumped out the tank and removed couple gallons of off color water/gas mix
- added a couple of gallons and re-pumped to clear some crud
-upgraded fuel hoses to low permentation ethanol fuel A1 hoses
-cleaned carb, filters
-added 0-15psi fuel pressure gauge
- stopped buying marina fuel [use a couple of jerry cans]
- every spring pump out bottom couple of gallons of old fuel.
This may sound a little extreme but I do not want a repeat of this fuel/tank problem at precisely the wrong time.