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Yamaha T99 2002stalls on acceleration

F

fredcc

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"Outboard will idle but stalls

"Outboard will idle but stalls when attemping to increase speed. Primer bulb will get firm but after a minute is soft again Can force engine to run at speeds above idle if primer bulb is repeatedly squeezed, other wize engine stalls.
Replacing primer bulb did not help."
 
Thanks for your response. Nee

Thanks for your response. Need I replace the entire fuel pump assy or does Yamaha have a kit to rebuild it?
 
"I replaced the fuel pump but

"I replaced the fuel pump but the problem still exists - thus it must be the carb as the vent in gas tank is open, the hose & primer bulb is new and the fuel pump is new. Nothing left except the carb. How is that cleaned?"
 
I did the same thing to my 9.9

I did the same thing to my 9.9 and the problem is still there. Is the carb difficult to clean? I also need a manual I will send you an email as well.
 
"I think its the carb, use sea

"I think its the carb, use seafoam, let it sit for a while, try to start. spray some gas in cylinder to aid starting."
 
Re: 9.9 yam...I've got the

Re: 9.9 yam...I've got the same motor..with maybe 20 hours use...starts and runs great for exactly 10 minutes..then just dies...
carb is clean as new..new tank bulb..etc...'
tried and double re checked everything...its over a month wait list for mechanic..???? someone said maybe coil?..any ideas??
 
"...ok this sounds stupid, but

"...ok this sounds stupid, but I'd check the connectors on the fuel line from the gas tank to the engine. I just got a new primer bulb last week and the connectors were so stiff that they wouldnt connect properly and werent letting enough gas through, unless I held the connector firmly to the gas tank. I repeatedly took it off and put it back on a couple of times and the problem went away..."
 
Watch Tempo connectors with Ya

Watch Tempo connectors with Yamaha tanks.I had trouble with these.The Tempo female hose end really didn't have enough spring tension to open the male barb on the Yamaha tank.
 
"Thanks everyone...re: yamaha

"Thanks everyone...re: yamaha 9,9 that dies after running perfect for ten minutes....I'm definately going to check those fuel connectors..the one that goes to motor is really hard to connect..and sometimes it seems to be..but isn't..going to bypass the connector and run it and see what happens this weekend..."
 
"Fred, problem still there? Al

"Fred, problem still there? All the 9.9 Yamaha's (15 hp block model) starting in 1992 have a problem with vapour lock on the fuel pumps. Motor runs fine at any speed until the engine temp is completely up then any attempt to run at anything above half throttle and the engine will starve out of fuel. The bulb is soft....If I caught mine as it was sputtering before it quit and pumped the bulb it would catch again and continue running. The fix...(Yamaha approved too!) I had a small aluminum block made that bolts to the end of the fuel pump. It has an inlet and outlet niple on it. I cut the water line going to the tell tale and diverted it through the block on its way out the telltale. The result is the water keeps the fuel pump cool and it no longer vapour locks. There are now many 9.9's up here with this add on , bolted to them...again with Yamaha's consent. You need to get screws long enough to accomodate the aluminum block. (replace the original ones) The only thing to watch is that the part allows clearence for the hood latch to clear. Good luck Rollie"
 
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