2000 90hp Johnson idle problem

[Wgb1978]

What will cause the engine to idle normal then rev up very high on its own

 

[racerone]

Does it keep reving high or does it stall after that episode ?

 

[Wgb1978]

Keeps reving

 

[Wgb1978]

To the point I have to turn the engine off

 

[Bmckinney]

Do you have a prop. on the motor during his time period ?

 

[faztbullet]

Is it a slow or rapid increase? Does it does it right after coming off WOT ?

 

[Wgb1978]

Yes it has the prop on it

 

[Wgb1978]

Slow but then gets faster

 

[Boobie]

Could be leaning out.( fuel problem).

 

[Wgb1978]

That’s what I’m thinking

 

[Wgb1978]

I cleaned out fuel tank,added new fuel lines and both fuel filters and still does the same. All 4 cylinders have 125# too

 

[Wgb1978]

New carb kits on all 4 carbs today, new bowls because of warp and still the same

 

[joereeves]

You say that the engine keeps revving to a point whereas you need to turn the key off.

With the hood removed so that you can observe the linkages if they are or are not moving by themselves, if the engine runs normally at idle for a period of time, then starts a increase in rpns.... that is the manner of running when one disconnects the fuel line and lets the engine run out of fuel (Not Recommended), especially a engine with more than one carburetor.

Keeping the above in mind.... Does pumping the fuel primer bulb cause the rpm to start dropping to normal?

Does the engine reach a peak rpm where it stops increasing if you do not turn the key off?

 

[racerone]

?----Checked engine cooling system ?----Issues with " quickstart " engaging.