Motor trouble
 

Question for all boat owners. I have a 50 hp Yamaha 2 stroke, I just had the carbs clean and went run it today and it ran fine on the first run. After fishing for about twenty minutes went to take off and it just stalled like it wanted to kill. It eventually plane out after about two Minutes of stalling. I put some fresh 93 gas and some oil into the gas. And I don't know what it is. It runs good on the first run but after stopping it always stalls to take off but it runs fine once it planes out. Any suggestion would be very helpful.

Sounds like your catching air. Is your bulb hard when it's bogging down?

Fuel. Strains to get on step. Check the pick up tube inside your tank for damages and make sure u Ain't got a kinked line. Bulb staying hard? Check plugs and if u gotta small 6 gal tank isolate the tank by buying a new one. Also could be connections on the gas tank or motor. Sounds like fuel restriction. Does it idle fine? No lean pop? Do you have to turn up fast idle lever to keep it running at first?

If its air it would seem like it'd run rough all the time not just to get on step

Not really.

Check your hoses. If you've run ethanol through them it could be your gas line deteriorating on the inside. Also make sure your vent is open on your gas tank. But could very likely be your hose. I would change your hose and go from there.

What year is your Yamaha?

I had a similar issue with my 06 yamaha 50 hp 2 stroke, it ended up being that i had an air leak where fuel was coming into the engine (the seal at the ball valve that plugs into engine was allowing small air leak)

couple things i learned while trouble shooting it were.

1) make sure that your emergency auto enrichment was in the right position (its the red switch on the front of your carbs) it should be in the completely up position.... not on or emergency...

2) change your plugs.. it's amazing how much better performance you get out of an outboard after changing plugs.


you said that you started running an oil and gas mix does the engine not have an oil mixer? if it does have you confirmed that its hooked up right after your carb work and that its pumping oil?

if your running double oil that could foul your plugs pretty quick.

sending you a PM as well that may help you troubleshoot it.

Check your fuel filter, i had that prob, changed 7.00 filter and was fine....cant hurt!

When it's getting on step that could be when it's catching its prime. It's Something simple.

What happens when you come off step? Does it stall when you try to take off again?

Yes the bulb is hard at that time

I just change the line when I bought the boat.

It gets on step as long as the motor is running. It stalls when I turn off the motor for longer than five minutes. But as long as it us running it tuns fine

check the auto enricher to ensure that it is working. it's a very easy check. let the engine idle on the lake for 5-6 minutes and then feel the auto enricher unit. It should be fairly hot to the touch. If it's as cold as the carbs that might be part of your problems.

I see that your saying that you changed the lines to the motor, did you change the fuel lines in the motor as well? with the hood off pump up your primer bulb and keep pressure on it... inspect each line under the hood to visually see if there is any seepage etc.

with it being something that only is happening after motor cools off it really makes me think its either a air leak into the gas or its your auto enricher unit.

what have you tried today? or at all for that matter

I didn't change those line but I did check them to see if they were leaking under the bulb being primed and it was no leaks anywhere.

Flip sent me these pics of his fuel filter. Looks durty to me. R Is it suppose to look like this

sent from my Galaxy NOTE II

sent from my Galaxy NOTE II

Have you heard of "hot soak". Google it and you will see what it is. When you turn your motor off for a few minutes it actually gets hotter and can cause problems with ethanol fuel. I don't remember exactly what it does but ( might evaporate fuel in the carb) but any carb motor running on ethanol fuel can do it. Gets worse in hot weather and only occurs when motor is turned off. It's a long shot but you should read up on it.

That's what it does or so I'm told. Buy some cartridges from academy and change yours out. Take filter off and slowly pour it in cup check for seperation. Squeeze bulp few times make sure good gas then connect it back. Do you notice your fuel sender whining a little louder? Trash gets in em and makes it struggle to dump fuel. Open end that too. If its trash then it's not giving enough fuel when u get on step that's y it's stalling

Take screws out carb bowl and if tip is green tinted then its ethanol issues

I had "kind of" the same problem on my last trip in the boat.

Engine rain fine the most of the day. Then when heading in that afternoon it "stalled" some after riding about 2 miles. When I say "stalled".....it would cut back to 2000 to 3000 rpm for 5 seconds and jump back up to 5000+ rpm for a few seconds.

If I slowed down to 3000 rpm, the engine would run smooth. I stopped to check the bulb and it was "tight". After checking the bulb, the engine ran good for 1/2 mile then started slowing down again.

I ran at 3000 rpm for a while, and all was good. But when I tried WOT again, it slowed down again so I stopped to look at the fuel line again.

Well......I found the problem.

When I bought the new boat, the fuel line had about 3 feet extra hose. To clean up the back compartment some, I coiled up the extra fuel hose and put a tie-wrap around the coil. This coiled hose had a kink in it. It did not look like it would restrict fuel flow, but after I took the tie-wrap off.....the engine ran fine.

I ran the boat yesterday with the vent open, checked the auto enricher and it was in the up position and same result. Bring it back to the mechanic. Thanks to everyone for the tips and suggestions.

Sounds like ethanol carb problems.


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