Carburator throttle plates.....

[mrcj001]

1975 Johnson 135 V-4

Last time out.....I developed a problem. The engine would stall when I put it in gear. I popped off the cover to take a look and noticed at idle the throttle plates were about 1/3 open. I read in the service manual that all outboards idle with the plates completly closed. When I completly close the plates while at idle the engine dies. The engine doesnt stall every time when I shift, but enough to aggravate me.

What gives??

 

[G DANE]

Re: Carburator throttle plates.....

You are probably running on 3 cylinders.

 

[Marvxyz2]

Re: Carburator choke plates.....

Re: Carburator choke plates.....

When the engine is warm and idling the choke plate should be wide open, or very slightly toward the close position. and when you close them when running the motor it will stall. It is one way to stop an engine.

 

[Vic.S]

Re: Carburator throttle plates.....

Are you really looking at the throttle valves or are you looking at the choke valves.

The choke valves are what you see in the inlet to the carb. They must be fully open when running. If you close them the engine will stop.

The throttle valves are at the back of the carb, much more difficult to see. They will be almost totally closed at idle but will open as the throttle control is turned up. At full throttle they will be fully open.

See THIS DIAGRAM The throttle valves are #7 and the choke is #5

 

[mrcj001]

Re: Carburator throttle plates.....

Are you really looking at the throttle valves or are you looking at the choke valves.

Sorry, I misunderstood the manual. I was refering to the choke plates...it makes since for them to kill the engine when closed.


I fooled with it today on the muffs.....I`m getting real good spark to all 4 plugs and the engine idles smoothly.


I have a leak down problem with the trim and tilt and I have to trim the engine up to get the engine to start and idle right when I`m on the water.

Is it that the backpressure is causing the problem??

Is adjusting the idle up a probable fix??