70 hp fuel issue

[barroomhero]

70 hp johnson The model number is J60ELCDS and serial is J7122208. Formerly under 70 hp stumbles. Cylinder three gets plenty of fuel, 1 and 2 don't get anything. Checked compression, 120, 110, 120. Cleaned carbs, checked needle and seat, checked reeds,switched carbs on 1 and 3 still no difference. What would cause one cylinder to get fuel and not the other two?

 

[R.Johnson]

Re: 70 hp fuel issue

Pull the hoses on those two carbs, and see if you have fuel flow.

 

[barroomhero]

Re: 70 hp fuel issue

Fuel comes out of the hose

 

[R.Johnson]

Re: 70 hp fuel issue

Does fuel come out of both hoses to the carbs giving the trouble?

 

[barroomhero]

Re: 70 hp fuel issue

Yes

 

[R.Johnson]

Re: 70 hp fuel issue

Is the throttle linkage in proper sync, in other words, are all three carbs fully closed together, and fully open

 

[barroomhero]

Re: 70 hp fuel issue

Yes, the top two cylinders just are not getting fuel for some reason. I checked the needle and seat on all the carbs, even tried switching the needle and seat with cyl 2 and 3. Nothing changed. Its really strange. With the plugs in fuel will spit back out of the carbs, which at first lead me to think float height or needle and seat but thats not the case. I am stuck on this one.

 

[fireman57]

Re: 70 hp fuel issue

With your carbs off take a strong flashlight and make sure there isn't a loose screw or mud dauber nest back on your reed valves. should be able to see pretty well in there with a halogen light.

 

[barroomhero]

Re: 70 hp fuel issue

Yeah, I took the reeds right out and they are fine. Nice n tight, couldn't see daylight thru them.

 

[R.Johnson]

Re: 70 hp fuel issue

At the bottom of the carb, and in the front, there is a bolt with a red washer under it, Remove this bolt, and see if fuel flows out. That will tell if fuel is truly getting into the carb.

 

[barroomhero]

Re: 70 hp fuel issue

Yes, fuel comes out

 

[R.Johnson]

Re: 70 hp fuel issue

Take a plastic coke bottle, punch a hole in the cap, and insert a plastic straw as used with a can of WD-40, fill with premixed gas. Run the engine with the airbox cover off, squirt fuel into the carbs that are not working, and see if there is any change.

 

[barroomhero]

Re: 70 hp fuel issue

Interesting idea. At this point the engine will not run. Only one cylinder is getting fuel. What would cause fuel to get to the top two carbs, fill the bowl, when the engine cranks over, it spits fuel back out the carbs? Loss of primary compression?

 

[R.Johnson]

Re: 70 hp fuel issue

The only thing I can think of that would spit fuel back out the carbs' when cranking would be a open reed valve. That would be unusual on two carbs. Have you had the air box cover off by chance. I once had a airbox with a mouse nest in it that done that. The engine sucked grain seeds' into the reed cages.

 

[barroomhero]

Re: 70 hp fuel issue

yeah, I even pulled the reeds out, they are fine. Can't see daylight thru them when they are closed. I just can't figure this one out.