1989 Yamaha 70 hp Power loss after warm up

Joined
Jul 3, 2005
Messages
1
Hello, I have read through all of the postings about power loss but my issue seems slightly different. I've just launched my boat after storing it for the winter. I had put in fuel stablizer before I stored it and cleaned the carbs. Checked the plugs (they were clean and dry) and removed the fuel filter to clean out for any gunk. The same methodical process I have done always. We launched it this week-end and it started right up and ran fine back to the dock, about a 20 minute run. An hour later we took a trip. It started and idled fine but two minutes in the journey it bogged down, sputtered and stalled. I got it started with no problem and did a short run and all was fine. We stopped for a short time (15 minutes) started back up and there was BIG trouble. Wouldn't run under load. I was able to get it started after alot of cranking, choking, priming etc.. but I dared not lower the throttle back from 4000 rpm or it would stall again.<br />I need some guidance to fix this or at least look in the right direction. I can't figure out why it will start up and run fine when cold but after it warms up I have problems. :confused:
 

rodbolt

Supreme Mariner
Joined
Sep 1, 2003
Messages
20,066
Re: 1989 Yamaha 70 hp Power loss after warm up

test compression then spark. if you rule those two out its usuaally fuel. may have some water or trash in a fuel bowl or possibly a bad fuel pump diaphram.
 
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