40 HP Johnson VRO

[bnice68978]

I'm not sure what year motor this is, where do I find the Model #, I'm having problems in full throttle, it cuts in and out, but doesn't stall, its fine at medium speed! Any help would be appreciated!!!

Thanks

 

[Silvertip]

Re: 40 HP Johnson VRO

Run wide open until it begins to act up. Then squeeze the primer bulb a few times or push in on the key to activate the choke/primer. If the engine picks up and runs fine for short distance, you have a fuel restriction or a weak fuel pump.

 

[Joe Reeves]

Re: 40 HP Johnson VRO

The model number is usually on a plate on the port (left) transom bracket. Hopefully you can find it, and if so, what is it?

Is that cut in/cut out a slow up and down type surge (fuel), or is it a sudden instantaneous and immediate type surge like yanking a plug wire off?

 

[bnice68978]

Re: 40 HP Johnson VRO

It seems to be a fuel problem... It cuts in and out slow, not instantly, like i'm giving it full throttle then letting off constantly..

 

[Joe Reeves]

Re: 40 HP Johnson VRO

Look for a lsight fuel leak somewhere between the fuel pump and the fuel supply. That would allow the fuel pump to draw air.

Also, do that test that Silvertip suggests (fuel restriction).

 

[bnice68978]

Re: 40 HP Johnson VRO

A storm is comming in, so I won't be able to get out on the water today, maybe tomarrow.... thanks for the quick responses... I'll post again tomarrow and tell you what I find!!

 

[bnice68978]

Re: 40 HP Johnson VRO

OK... I took the boat out today and when I am full throttle, and pumping the primer bulb, it runs fine... Starts acting up again about 10 secs. after I stop squeezing bulb!! Fuel Restriction Problem!!!! Should I replace the hoses and such going to the fuel tank?

 

[Joe Reeves]

Re: 40 HP Johnson VRO

A fuel restriction would cause the primer bulb to be drawn flat and if pumping the bulb was possible, the restriction would still be there making it impossible to supply fuel.

In essence, in pumping the fuel primer bulb, you were acting as a manual fuel pump and you were overriding the engines fuel pump.

Bottom line..... if no leaks exist, AND IF the pulse line leading from the pump to the crankcase is not broke or split, it would appear that the pump is faulty.

Did you find the model number?

 

[bnice68978]

Re: 40 HP Johnson VRO

I didn't find the model number yet... I looked all over the place.

I did find a torn fuel line, replaced it, but still doing the same thing. Is the fuel pump small with 3 fuel lines comming off of it, and wires comming off of it?

 

[kmk_7110]

Re: 40 HP Johnson VRO

when you pumped the bulb and ran it did u see a line of gas behind you after you shut down or slowed down. If so then it is probably the fuel lines or fittings. I know i had this type of problem with my 64 18hp rude a while back and it was just a fuel line end, the seal was broken. I bought a new fuel line and keep the extra with me as a spare because it will still work in a pinch.

 

[bnice68978]

Re: 40 HP Johnson VRO

I'll check for a line of gas the next time I take it out... I didn't really look to see.

 

[bnice68978]

Re: 40 HP Johnson VRO

Model #is J40TLCCS
Year: 1988

 

[bnice68978]

Re: 40 HP Johnson VRO

Today I took the caburators apart and found that the float valve seat spring was broken and just hanging there. I bought 2 rebuild kits and rebuilt the carbs.... Took it out tonight and it ran great, all fixed!!!! ... Thanks for all the advice!! Happy Boating!!!!!