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Moonshiner

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Ive got a yamaha 150 hp outboard. It only starts with starting fluid. After that it itl run like a scalded dog. Itl crank right back up but if i let it set for 10-15 mins it wont start. Back to the starting fluid. Ive run 2 bottles of sea foam through the gas tank & sprayed a half can of carb cleaner in them. Any ideas? Thanks
 
I'm assuming this is a 2 stroke carb'd motor since you're spraying carb cleaner. Let us know if not. When was the last time you pulled the carbs and cleaned the jets, checked height of floats?

The chemical products you're using, sea foam and carb cleaner, will not solve engine problems. Sea foam in particular is a preventative maintenance product. Carb cleaner should be used only when cleaning deconstructed carb parts, such as using it to soak jets to loosen debris. Despite the intended uses of carb cleaner, which is written on the can, when you spray it into the throttle body it also eats the lubrication provided by the engine oil.
 
Old fuel from last year? New fuel mixed with old? History on motor would help, First use this year? New owner of engine and boat? Was it stored properly last season? Serial # might help,year, What's your starting procedure? Any problems last year? The fact that once started she runs great eliminates compression and spark issues, Pull a fuel bowl and take a look before pulling carbs,it might give a clue, if not thread #2, Pull carbs,soak and clean thoroughly every nook and cranny,jets etc.
 
Stop using starting fluid on your engine!


After you post what your engine is, 2 stroke or 4 stroke.....

You need to verify a good ignition spark at cranking speed.
 
My mate has a Yamaha 50hp two stroke I bought it new in 2013 and has had troubles missing thought it was dirty fuel it played up yesterday limped back to ramp pulled bottom plug out and the end looked like it had been smacked on the end did a pressure test and nothing what's your thoughts has the piston come a drift
 
I just bought this boat & 150hp rig this spring. Its ben setting in a garage for 2 years. The previous owner said hed only cranked it about once a mo using the muffs. Im not a mech at all on this engine. It scares me to even think about making matters worse. It looks like its got 6 carbs. Yes its a 2 stroke. The starting fluid im using is susposed to be for 2 stroke motors. It has upper lubrication in it. The napa clerk said it was ok. I believed him. That alone shows you how smart i am. It ha a good spark. Itl knock your #$/& off. Il have to find ser #. I do know its a 91 mod.
 
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Yes the bulb gets hard but after it sets for a while it does loose its firmness. It seems like has to be in the fuel system because it runs and idles to good. But here again im no mechanic.
 
Moonshiner said:
Yes the bulb gets hard but after it sets for a while it does loose its firmness. It seems like has to be in the fuel system because it runs and idles to good. But here again im no mechanic.
Click to expand...

After the bulb gets hard, if you keep constant pressure on it does it stay hard or does it slowly collapse?
 
As long as its running i think it stays hard. Its when i shut it off is when it looses it firmness just a little but after around 15 mins. I need to check this out closer. Iv not paid that much attention to it. I will tho. Thanks. I have to wait on one of my fishing buddies to bring their boat too. I dont wont to get stranded again.
 
If it has a manual choke as well as the key operated one like some of them do, try the following -
1) pump the bulb till hard
2) pull out the manual choke
3) lift the fast idle lever until it has moved the idle position up noticeably (some levers do nothing in the first few inches of 'easy' travel). If you have the controls without the fast idle lever push the center 'gear disengage' button in the throttle control lever and lift the idle position using the throttle lever
4) wind the engine over to see if it will kick or start (may take 2 or 3 seconds of winding)
5) as soon as it starts you need to close the choke and pull back the fast idle. If it starts then stops. try starting again without the choke

We have had a lot of these engines over the past 20 years and the fastest cold start procedure was like this for all of them once they got some age and hours on them. You could wind them over all day without the choke and they wouldn't start.
 
I wont to thank everyone for helping me with my motor troubles. A shadetree mechanic cleaned the carbs, did some adjusting, new bulb, new filter, plugs, & fresh gas. I took it out & thought it was on fire it smoked so much. Spit & sputtered. Whatever he did worked. He would get upset cause i kept tellin him what you all was telling me on this forum. I cant pinpoint what the problem was but a great big thanks to you all.
 
Your right. Wish everbody could take a lesson from my mistake. Dont ever put your motor up for the winter without completely preparing it. Just a little stabilizer doesnt always work. And it can get costly.
 
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