"Posted for brother in law

"Boat motor will not idle without hitting the electric choke every few seconds. Runs fine from one quarter throttle to full throttle but I have to take my time getting it up to or it will stop (I used to be able to hammer the throttle from idle with no problems). I checked fuel filter, replaced spark plugs and added a can of Sea Foam to gas tank. I’m thinking it has something to do with the fuel pump. "

if you guys have any ideas or suggestions please share

Chris

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Chris Grauer- "To protect, promote, and grow the sport of spearfishing" www.spearfishingplanet.com

Chris did he by chance put in some of that wonderful ethanol gas, if so it probably cleaned something loose from the tank or lines and it sounds like he may have to clean the carbs to fix it. It is starving for fuel thats why the choke helps. Not likely a pump, if it was it would lose power at higher rpms too.

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Gotta go with Roland on this... or he may have a little more water in the tank then the sea foam can handle.

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James McKeever

You seem to be right on target with it being a fuel problem. You did not mention some important facts such as what brand motor,year and size but I'll throw out a few things that have plagued me on different motors: some motors have another fuel filter on the block sandwiched in the fuel pump, it is usually a screen so check that one also. Does yours have a small pump on the block that may have gone bad? RECHECK all your stainless steel worm gear clamps on the suction side, any air entry will knock down your performance. Pinched or clogged lines will drive you crazy, do you have good flow up to the motor? This next one sounds really dumb but here goes (with an explanation). My tank holds 71 gallons but only 68 are usable because of the height of the pickup tube, sooooo, do you have enough gas? ouch, that one hurt!! Hope some of this might get get you going again. We have some real pro's out there so stand by for more ideas.

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A candle loses no light lighting another candle.

sounds like the mechanical fuel pump has gone bad. What kind of outboard is it and i can give you the pressure specs that it should be putting out at idle.

Calvin

My bad I forgot the engine info.

The motor is a 2002 Yamaha 115TRA 2-stroke with 200 hrs.

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Chris Grauer- "To protect, promote, and grow the sport of spearfishing" www.spearfishingplanet.com

Take the bowl off the carbs, clean out the low speed jet, reassemble, make sure he's not using the old gray tubing for a gas line. The ethanol will turn it to goo.

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In the beginning of a change the patriot is a scarce man, and brave, and hated and scorned. When his cause succeeds, the timid join him, for then it costs nothing to be a patriot. ~Mark Twain

I agree with marcus. To rule out a fuel pump, just have someone pump the bulb. If that cures it, its the fuel pump or screen in pump. The small on block pumps have a diaphram and they get a small air leak and dont pump good at an idle if leaking. But as was said, if you had a bad fuel pump it would be worse at high speed, most likely.

Check for water in oil reservoirs - Yammies work on negative not positive pressure and can suck in water.

Installed new fuel pump and still have the same problem. It could be the carb but I noticed something today. My gas tank vent (at least I think it's a vent) on the side of my boat is broken. It happened a few trips back when someone jumped on the boat when it was too close to the dock. This problem with the boat not idling started right after that trip. So, I'm thinking it has something to do with that. After it broke, the hose fell and got wedged in between the foam in the haul. I haven't tried fixing it yet because I want to know if it has a filter of some sort that could be clogged. Anyone have any suggestions. The boat is Thanks for your help.

Do get a new vent, and install it. You dont want fuel venting into your boat. You might have a clogged vent line, but that would probably be more of a high speed thing, most likely, or maybe it is clogged. Check that. If when you open the tank fill it does run better, then you know its the vent. Fix the vent none the less.

If you think its the vent (fix it anyway) just open the gas cap as a vent and you will have your answer. The vent will only have a screen that faces down and back towards the rear of the boat.

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Thanks to everyone that helped me on this. Had a mechanic look at it and it was in fact the carb. Needed to be cleaned and rebuilt. They also added a water fuel separator and said it would help keep the carb clean. Mechanic told me to not go more than 1 month without starting motor and letting it run for at least half hour. Also said I needed to add the Yamaha fuel stabilizer and NEVER to add Seafoam. Runs great now!