Not an antique, but I need some help.

[wiscoboater]

Hi Guys,
I have a 77 Johnson 35 that is just giving me fits. I’m hoping one of you can help out here. When I got the motor it was a non runner. Traced the problem down to the needle being stuck in the seat. Rebuilt the carb and it ran OK for awhile. It has a very persistent lean sneeze followed by konking out at idle. Restart it and it runs about 5 seconds and konks out…over and over. I have spark jumping a 1/4 inch gap on the tester, 105 compression on the top and bottom. If I accelerate the motor it runs great. I have richened the mixture at idle being that it only has a idle mixture adjustment. does not seem to help. now when I try to accelerate it, it is very sluggish not running well there either. I’m scratching my head here with this thing. Bad/weak fuel pump? coil going bad? Anyone have any suggestion where to look next?

Thanks guys,
Wannabe

[cajuncook1]

quote wannabe outboard guy:

Hi Guys,
I have a 77 Johnson 35 that is just giving me fits. I’m hoping one of you can help out here. When I got the motor it was a non runner. Traced the problem down to the needle being stuck in the seat. Rebuilt the carb and it ran OK for awhile. It has a very persistent lean sneeze followed by konking out at idle. Restart it and it runs about 5 seconds and konks out…over and over. I have spark jumping a 1/4 inch gap on the tester, 105 compression on the top and bottom. If I accelerate the motor it runs great. I have richened the mixture at idle being that it only has a idle mixture adjustment. does not seem to help. now when I try to accelerate it, it is very sluggish not running well there either. I’m scratching my head here with this thing. Bad/weak fuel pump? coil going bad? Anyone have any suggestion where to look next?

Thanks guys,
Wannabe

When you rebuilt your carburetor, did you remove the fixed high speed jet and soak it in cleaner and blow it out with air. Item number 31 in the diagram. Please refrain from sticking a drill bit or wire in the jet to clean it, because you could accidentally alter the size of the jet. It is metered size wise for a specific delivery. As for idling, in the past when the needle was stuck in the seat, it could have damaged the seat and making it much more difficult to dial in a smooth idle.

[chris-p]

I would first ensure it is a lean sneeze, and not an ignition miss. I like to use inline neon spark testers for this to watch quality of spark while running, and see if flutters in the tester corresponds to the miss or sneeze.

If indeed spark stay strong throughout the run, I would look for the air leak.

Start at conector. Fuel lines. Crankcase. Possibly crank seals?

First though I would try new plugs before anything major.

[frankr]

Trash in the idle ports under the #5 core plug? #2 Lead shot missing? That carb looks a bit different than what I’m familiar with. Does the idle mixture control air instead of fuel?

[frankr]

BW, maybe not an "Antique" but at 38 years old, it certainly qualifies as a "Classic" and qualified to appear at aomci.

[wiscoboater]

quote cajuncook1:

quote wannabe outboard guy:

Hi Guys,
I have a 77 Johnson 35 that is just giving me fits. I’m hoping one of you can help out here. When I got the motor it was a non runner. Traced the problem down to the needle being stuck in the seat. Rebuilt the carb and it ran OK for awhile. It has a very persistent lean sneeze followed by konking out at idle. Restart it and it runs about 5 seconds and konks out…over and over. I have spark jumping a 1/4 inch gap on the tester, 105 compression on the top and bottom. If I accelerate the motor it runs great. I have richened the mixture at idle being that it only has a idle mixture adjustment. does not seem to help. now when I try to accelerate it, it is very sluggish not running well there either. I’m scratching my head here with this thing. Bad/weak fuel pump? coil going bad? Anyone have any suggestion where to look next?

Thanks guys,
Wannabe

When you rebuilt your carburetor, did you remove the fixed high speed jet and soak it in cleaner and blow it out with air. Item number 31 in the diagram. Please refrain from sticking a drill bit or wire in the jet to clean it, because you could accidentally alter the size of the jet. It is metered size wise for a specific delivery. As for idling, in the past when the needle was stuck in the seat, it could have damaged the seat and making it much more difficult to dial in a smooth idle.

I did have the carb completely apart, soaked it in acetone. I did not stick anything into jet, wire or drill bit, nothing at all. I may try taking it apart again and see if I missed anything. The gas tank was squeaky clean with fresh fuel and oil at 50:1. I did not blow it out, that I know for sure.

[wiscoboater]

quote Chris_P:

I would first ensure it is a lean sneeze, and not an ignition miss. I like to use inline neon spark testers for this to watch quality of spark while running, and see if flutters in the tester corresponds to the miss or sneeze.

If indeed spark stay strong throughout the run, I would look for the air leak.

Start at conector. Fuel lines. Crankcase. Possibly crank seals?

First though I would try new plugs before anything major.

I only have an open air tester. Spark is white, not blue. Almost seemed a little weak. I did notice a crack in the bottom coil.

[wiscoboater]

quote FrankR:

Trash in the idle ports under the #5 core plug? #2 Lead shot missing? That carb looks a bit different than what I’m familiar with. Does the idle mixture control air instead of fuel?

Got me Frank, A 77 is very new to me. The whole coil, power pack, 50:1, thing is above my pay grade. Where is the #5 core plug? I did pull the core plugs on the carb when I rebuilt it and blasted out the orifices with carb cleaner. When I did that it came out somewhere else so I thought all was good?

[wiscoboater]

Ok, I see #5 in the diagram Frank. Yes, I did pull that and blasted out the ports with carb cleaner. I then installed the new plug, staked it in place and sealed the top with my wife’s clear nail polish. (gosh that’s embarrassing to say out loud)

[Mumbles]

Check for wear on the throttle shaft where it sticks out on both sides of the carb body. An air leak here will cause a sneeze at idle. Maybe raising the float level a bit will help to.

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