Boat stalls at high rpm

[83 Cs7]

I have a 83 cobalt with a 305 v8. When at full throttle the engine will cut out and go back to idle , If kept at 1/2 throttle runs fine. I replaced the water seperator filter, and the fuel filter in the carb. possible fuel pump? I also replaced the condensor and points at the begining of the season, could a timing issue cause this?

 

[gdombroski]

Re: Boat stalls at high rpm

Replace your anti siphon valve, about $15. A sticking one won't provide enough fuel to feed the secondary's and will cause it to do what you are experiencing. At least mine did.

 

[sarantis]

Re: Boat stalls at high rpm

First of all use an external tank.if this is not easy for you replace the aluminium hose from pump's outlet to the carb inlet with a clear flexible one and put a friend to drive and watch if the fuel flow is continuous without bubles.If it is then check the carb(secondaries opening)

 

[jp89bayliner]

Re: Boat stalls at high rpm

I have a 83 cobalt with a 305 v8. When at full throttle the engine will cut out and go back to idle , If kept at 1/2 throttle runs fine. I replaced the water seperator filter, and the fuel filter in the carb. possible fuel pump? I also replaced the condensor and points at the begining of the season, could a timing issue cause this?

Keep us posted I am fighting the same thing. I havent replaced the anti syphon valve yet but Iam going to tommorow.

 

[83 Cs7]

Re: Boat stalls at high rpm

Replace your anti siphon valve, about $15. A sticking one won't provide enough fuel to feed the secondary's and will cause it to do what you are experiencing. At least mine did.

exactly where is the anti siphon valve located? and my boat is only a dual carb

 

[jp89bayliner]

Re: Boat stalls at high rpm

exactly where is the anti siphon valve located? and my boat is only a dual carb

There should be a 90 degree fitting on the fuel line outlet from the tank. It has a check ball inside of it and a small spring that are known for sticking.

 

[cobalt cs7 1982]

Re: Boat stalls at high rpm

my 1982 cs7 with a 305 v-8, 198 hp, has only a 2 barrel carb, i bought it from the original owner and with it came a service bulletin from cobalt about this, when i get home i will scan it, it had something to do with the pick tubes as stated above. this condition accorded also during turning at speed,
also what is your cs7's top speed.
thanks mike

 

[GeorgeF]

Re: Boat stalls at high rpm

I have a 1984 Chapparral that was experiencing the same thing. Check the filter in the pick-up tube my was totally caked and not letting enough fuel through I just figured it out but snaped the fitting trying to put it back so now I'm trying to find the 90 degree fitting and the one connected to the hose. If any one knows where I might find them it would be great!!!

 

[MikDee]

Re: Boat stalls at high rpm

my 1982 cs7 with a 305 v-8, 198 hp, has only a 2 barrel carb, i bought it from the original owner and with it came a service bulletin from cobalt about this, when i get home i will scan it, it had something to do with the pick tubes as stated above. this condition accorded also during turning at speed,
also what is your cs7's top speed.
thanks mike

Put a 4bbl on that motor, and it'll automatically be a 228-230hp/305, that's the only difference

 

[MikDee]

Re: Boat stalls at high rpm

I have a 1984 Chapparral that was experiencing the same thing. Check the filter in the pick-up tube my was totally caked and not letting enough fuel through I just figured it out but snaped the fitting trying to put it back so now I'm trying to find the 90 degree fitting and the one connected to the hose. If any one knows where I might find them it would be great!!!

A good old fashioned marine supply should have those tank fittings, with the tube on them. Or you might be able to make your own, by getting a double tapped pipe threaded bushing, 3/8" inside, 1/2", outside NPT (national pipe thread) "Or choose your own particular size" then a piece of threaded pipe to go down into the tank. A good plumbing supply should have what you need, (think of the fuel oil supply line coming out of your home fuel oil tank)