9.9 4 Stroke Stalling at High Speeds

Hardcore

Petty Officer 3rd Class
Joined
Dec 5, 2007
Messages
87
at high trolling speeds my 1990 9.9 4 stroke hi thrust will stall out and die after a minute or so. usually if i pump the bulb it will buy it another minute. sounds like a fuel pump but its new (the old one was leaking gas into the crankcase). bulb is always hard and its running off the main tank with the main motor. would a float problem also cause this?

it will idle and putt around for ever but under much load it will sputter out and die. i took off the fuel line from the fuel pump outlet and it just drips fuel(at best) at idle. not like the spurt it describes in the manual. i took the pump apart and it looks fine.

some people have said that im running too large of fuel line to it. im running 3/8 hose from the water separator to the motor and the motor has 1/4 on it. the manual says not to use too small hose but says nothing about too large. and i've never run this thing at high speeds before so i cant compare it. its running off the main tank.
 

99yam40

Fleet Admiral
Joined
Sep 7, 2008
Messages
9,127
Re: 9.9 4 Stroke Stalling at High Speeds

Does the fuel just drip out also when you pump the primer bulb?
Sounds like a restriction some where
 

Hardcore

Petty Officer 3rd Class
Joined
Dec 5, 2007
Messages
87
Re: 9.9 4 Stroke Stalling at High Speeds

Does the fuel just drip out also when you pump the primer bulb?
Sounds like a restriction some where

no, it shoots out fine with the bulb. nice column of gas with the bulb.
 

GreenHead870

Recruit
Joined
Oct 23, 2010
Messages
1
Re: 9.9 4 Stroke Stalling at High Speeds

Are you running a water fuel seperator with two inputs two outputs? If so, you maybe sucking air in from the other motor if you dont have an anti siphon valves installed on the outlet side of the water fuel seperator.
 
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