1995 Yamaha 150 won't get up and go

robsco · Jul 24, 2004

Hello to all, I just found this forum and hope ya'll can help. I just bought a 22' Bay Stealth center console boat with a '95 Yamaha 150 Saltwater Series engine. The engine will start okay and idle good but will not get up on top and plane out. I have put on the correct size prop, changed the fuel filter and the spark plugs. It seems to be starving for gas. Max rpm is around 2200. The cable lets the throttle go to the limits. Any ideas? Thanks

robsco · Jul 24, 2004

Re: 1995 Yamaha 150 won't get up and go

Sorry....didn't read the suggestions for new users post. Just ordered a manual and will use search feature to try to find posts on related problems. Sorry.

rodbolt · Jul 24, 2004

Re: 1995 Yamaha 150 won't get up and go

hello when was the last time it ran correctly? gas will gum up the carbs and cause this, fuel pump diaphrams will as well. post more info and we will try to help

robsco · Jul 25, 2004

Re: 1995 Yamaha 150 won't get up and go

Thanks for the reply...I just bought it so I don't know when it last ran right. I have no history on the boat. I've read several posts about fuel pumps and rebuilding carbs so I guess I'll start there? Thanks.

edodds · Jul 25, 2004

Re: 1995 Yamaha 150 won't get up and go

Skytexus, have you checked compression on all the cylinders ? You said you changed the plugs, but did you test for spark as well? My engine pulled this once and it was a coil that was out, $60 and the problem was solved.

robsco · Jul 25, 2004

Re: 1995 Yamaha 150 won't get up and go

Thanks edodds....I'll get on it. What do ya'll recommend for a spark test method? I am waiting on a manual so is there anything else you guys think I should be doing in the meantime? Appreciate the help, this is a really good forum. Glad I found it.

Ray Neudecker · Jul 26, 2004

Re: 1995 Yamaha 150 won't get up and go

Basically, you should check compression and fire before moving to the next stage of fuel restrictions. Using a timing light has been the easiest method for me of checking fire. Mark the flywheel with whiteout and check for the proper fire on each cylinder. The marks are there, you just high light them so you can see them with the light easier. It does sound like a fuel restriction. I would go ahead and change the fuel pumps due to age and then clean and adjust the carbs if fire and compression are OK. There are so few firing problems with a Yamaha, that step gets skipped many times. Good Luck.

robsco · Jul 26, 2004

Re: 1995 Yamaha 150 won't get up and go

Thanks Ray. Parts store here I come.

robsco · Jul 27, 2004

Re: 1995 Yamaha 150 won't get up and go

Compression and spark check out okay, 2 new fuel pumps installed. Never saw a fuel pump like these...seem to work off of vac or pressure from the head. Will check out after work today. If carb work is necessary is it very difficult? I am pretty handy but carb work sccares the $#!% out of me. I am still waiting on a manual and would like to get running right before the weekend. Thanks for all the help, it is appreciated.

rodbolt · Jul 27, 2004

Re: 1995 Yamaha 150 won't get up and go

carb work on your yammy is simple most the problems are in the fuel bowl area. dont try to remove the idle jets. dont keep trying to run it with clogged carbs either good luck and keep posting

robsco · Jul 28, 2004

Re: 1995 Yamaha 150 won't get up and go

Turns out the linkage to the spark advance was broke off. At least I know when the fuel pumps were last changed

Thanks for the help.

batkins761 · Jul 28, 2004

Re: 1995 Yamaha 150 won't get up and go

I had a problem where I would loose about 30% power (rpm) off and on for no apparent reason. It ended up becoming so frequent that I had to deal with it. After a lot of testing and mucking around, I resigned myself to overhauling the carbs. It was far easier than I imagined! I found the problem, the lower carb had a big gobber in the float bowl that was getting caught in the intakes and shutting down 1/3rd of my motor! The key to remember is DO NOT DUNK! Use a carb cleaner to wipe off the mating surfaces, etc. The rest of the carb has a sealant that keeps it from getting contaminated with condensation and gas. Dunking in a carb cleaner (as you would do with a auto carb) will strip that off. Good kits with a good manual (I used Clymer) made it an easy weekend job. b

Ray Neudecker · Jul 29, 2004

Re: 1995 Yamaha 150 won't get up and go

New one on me about the sealant and not dunking the carbs. For the last 20 years I have been not only dunking Yamaha carbs but actually soaking them over night in carb cleaner. I have also done the same for 40 years on other brand carbs. Amazing how many time this has cured the problems without creating a problem. The plastic OMC carbs are the only ones I know of in marine carbs that you should not dunk.

1995 Yamaha 150 won't get up and go

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