1986 Johnson GT150 dies at Full Throttle

[GunnerSC]

This outboard cranks and runs great, but when you open it up to full throttle it just about gets planed out and BAM!!! it dies like it was shot. The carbs where rebuilt 6 months ago, and all fuel line are good. The VRO oil has been taken off. I was thinking it may be the fuel pump any suggestions? Oh and the bubble stays up.

 

[emdsapmgr]

Re: 1986 Johnson GT150 dies at Full Throttle

Some additional information would be helpful: Does it start right back up again after it quits? Will it run 4000 rpm all day and not quit? Does it have spark just after it quits? What happens if you constantly prime the fuel hose bulb, forcing fuel into the carbs-will it still die at full throttle? Is the hose bulb collapsed when the engine quits? If you removed the single VRO and went to the old (pre-mix) style pumps, the factory always installed two pumps on the earlier V6 engines.

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

Some additional information would be helpful: Does it start right back up again after it quits? Will it run 4000 rpm all day and not quit? Does it have spark just after it quits? What happens if you constantly prime the fuel hose bulb, forcing fuel into the carbs-will it still die at full throttle? Is the hose bulb collapsed when the engine quits? If you removed the single VRO and went to the old (pre-mix) style pumps, the factory always installed two pumps on the earlier V6 engines.

Yes, It does start right back up after it quits. As long as you are not creating a wake it runs good. So not sure about the 4000 rpm's. Have not tried to pump bulb while at full throttle. The bulb does not collaspe at all. Another thing is sometimes it reacts to the thottle and goes for a min. then dies back to like 1/4 throttle without moving the thottle. Hold the key in and it seems to react to that and runs, then starts acting up again then just dies. I didn't remove the pump just disconnected the oil injection part if that makes sence. I hope this helps. Thanks

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

i hope that helps

 

[ondarvr]

Re: 1986 Johnson GT150 dies at Full Throttle

If when you push in the key (activate the primer) it runs better, then it is a fuel issue. Did it run correctly before you disconnected the oil pump? Check the carbs again and also look for air leaks in the fuel lines.

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

OK new info, when you pump the bulb it runs good. I will be checking for leaks in fuel lines and air leaks. Thank you so much for your help.

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

Ok i have checked all the fuel lines and they are in good shape. As far as I can tell all hoses are in good shape. The bubble is good and fuel filter is good. thanks again.

 

[ondarvr]

Re: 1986 Johnson GT150 dies at Full Throttle

If pumping the bulb works, then there's something not right with the fuel pump, check it again, or you need a new one (or rebuild if you can get parts).

 

[jonesg]

Re: 1986 Johnson GT150 dies at Full Throttle

I'd replace the pump with a sierra "fuel only" pump , they're around $70.

 

[Jayboid]

Re: 1986 Johnson GT150 dies at Full Throttle

It sounds like your carb float chambers are running dry when under a high RPM load. It could be that your fuel pump needs replacement. It could be that you are no longer getting enough vacuum pulse from your crankcase to run a vacuum-pulse fuel pump due to a crankcase leak or worn rings. It could be that your carb float levels are set incorrectly. Aint boating fun?

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

Does anyone know which sierra pump would be for this GT 150 Fuel only pump? Thanks so much for your help.

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

bump! I really need this part.

 

[GunnerSC]

Re: 1986 Johnson GT150 dies at Full Throttle

Yep this is it!! Thanks

I need this part still

 

[nymack66]

Re: 1986 Johnson GT150 dies at Full Throttle

I think he is referencing a electronic fuel pump with a regulator not a OMC pump ..
As for your woes I don't think its fuel ,Use a flash light and inspect under the flywheel any sign of melting stuff is indicative of a stator going bad ..

 

[jriegle04]

Re: 1986 Johnson GT150 dies at Full Throttle

before you buy the pump you should check your anti-syphon valve. those have a tendency to cause a lot of problems. it is in the brass barb fitting at the fuel tank. if your tank is lower than your motor you can remove it and drill out the ball bearing inside and reuse that fitting.

 

[jonesg]

Re: 1986 Johnson GT150 dies at Full Throttle

Yep this is it!! Thanks

I need this part still

its definately the pump or associated lines. Check the vac valve too.

how can anyone hope to look the part up ,
you never posted your model number.

Its probably available right under your very nose.. here on iBoats.

if you call iboats customer service trhey are very good, get your model number first.