6 HP stalls above half throttle

[mleea]

I have a 73 6HP Johnson the dies above half throttle. I have put a kit in the carb. I checked fuel filter. I tried pumping primer bulb to see if fuel pump might be week. The motor runs smooth to about half throttle. If I go above that point the motor dies. I thought it had to be fuel related but now I don't know. Any ideas?

 

[ondarvr]

Re: 6 HP stalls above half throttle

As it starts to die pull the choke out and see if it stays running.

 

[Daviet]

Re: 6 HP stalls above half throttle

Sounds like jet is plugged, when you overhauled the carb, did you remove the high speed jet in the bottom of carb bowel, clean it with a fine wire and blow all the jets out with compressed air?

 

[mleea]

Re: 6 HP stalls above half throttle

I did remove the high speed jet and clean it. It seems the holes are really quite large. Maybe I missed a smaller hole in the jet. I saw only one at the bottom and 3 small ones about half way up going across the jet. I can get the engine to rev higher by pulling the choke out for a second and putting it back in. It won't run long and if I leave the choke out it will die out. Do you think the problem is still fuel related or could I have some kind of ignition problem?

 

[Elbo]

Re: 6 HP stalls above half throttle

Funny how we are all having the same problem with these sixes.I 'm telling you the needle and seat don't match.

 

[Elbo]

Re: 6 HP stalls above half throttle

By the way these are the same carbs up to 79.

 

[Daviet]

Re: 6 HP stalls above half throttle

The high speed jet is screwed into the bowel behind the 7/16 drain plug for the bowel. It takes a special tool or a screw driver that just fit in the hole. It is about 1 inch into the bowel. Is that the one you removed or was it the high speed nozzle that goes up from the bowel to carb body?

 

[crxess]

Re: 6 HP stalls above half throttle

Remove carb, remove drain plug, clear high speed orifice behind plug with a piece of wire.
Get a can of spray carb cleaner, attach the straw, fit against orifice and spray to confirm it is clear and flow is strong.
The vertical tube is NOT the jet.

Remove the low speed adjuster. Spray through and confirm a strong spray from the tiny holes in the carb throat.

Make sure the small AIR HOLE at the top of the carb is open not blocked.

 

[kenmyfam]

Re: 6 HP stalls above half throttle

Does still seem like there is an obstruction in the fuel system.

 

[mleea]

Re: 6 HP stalls above half throttle

Thanks for all the help. I didn't understand where the high speed jet was. The motor is at my cottage and I won't be able to try the solutions for a couple weeks but I am sure that is the problem. I'll reply again once I've got it running.