Johnson 1961 3HP wont speed up

[59 Fatty]

I got this little motor started after new plugs, new wires and boots, new points and condensers, new coils, new impeller and new oil. With fresh gas and fresh oil in the mix, it started right up. But the adjustments for the jets seemed to make no difference. What you don't see in the video, is what happened after I started it again. I turned off the petcock to shut off the fuel flow, and just a bit before it died it revved way up and sounded great. What am I doing wrong, or what did I not do? I am puzzled on this one. Please help.....I have another post on the boat renovation that this motor is a kicker for, but I'm desperate to get noticed by an expert or someone that this has happened to before. Thanks

 

[iggyw1]

It sounds like a fuel problem. First of all, it's normal for the motor to rev up after you shut off the fuel just as the carb is running out of fuel. Make sure the primer ball is staying full (hard) when the motor is running. Squeeze the ball when it is running and see if it runs better, if it does, you are sucking air somewhere and losing the prime. It could also be a timing problem if it is running good when idling but will not speed up.

 

[F_R]

Well of course since that motor has an integral tank, there is no primer bulb. But it does sound like it is running too rich. Has somebody had the carburetor apart? Perhaps they didn't put in a new gasket around the main nozzle. Or they got the slow speed and high speed needles swapped? Or you don't have a proper pre-set on them. You do have the choke knob pushed in, right? Nothing obstructing the air inlet, right? Lots of possibilities.

High speed needle should be 3/4 turn out from lightly seated. Slow speed 1 1/2 turns. Those settings will get it started and you will need to reset them for best performance on a boat, on the lake. They will probably be too rich at the suggested presets. So turn them in till it starts to falter, then back off till it regains power. High speed first.

Yes, even when set up right it will speed up a bit right when it runs out of gas. But not drastic or spectacular.

 

[59 Fatty]

Well of course since that motor has an integral tank, there is no primer bulb. But it does sound like it is running too rich. Has somebody had the carburetor apart? Perhaps they didn't put in a new gasket around the main nozzle. Or they go the slow speed and high speed needles swapped? Or you don't have a proper pre-set on them. Lots of possibilities.

High speed needle should be 3/4 turn out from lightly seated. Slow speed 1 1/2 turns. Those settings will get it started and you will need to reset them for best performance on a boat, on the lake. They will probably be too rich at the suggested presets. So turn them in till it starts to falter, then back off till it regains power. High speed first.

Yes, even when set up right it will speed up a bit right when it runs out of gas. But not drastic or spectacular.

Yep, no bulb. And yes, I had the carb apart and rebuilt it. I did put a gasket around the main jet, and it seemed ok. I have thought about having the high and low speed jets swapped. I'll check that, the long skinny jet is the slow jet and goes on top right?

Thanks F!

 

[59 Fatty]

Well the jets are in the right places, Is the gasket around the main jet at the base is more of a thick washer (red) or a donut shaped rubber ring (black)?

 

[nwcove]

Yep, no bulb. And yes, I had the carb apart and rebuilt it. I did put a gasket around the main jet, and it seemed ok. I have thought about having the high and low speed jets swapped. I'll check that, the long skinny jet is the slow jet and goes on top right?

Thanks F!

when you say you rebuilt the carb, you do mean that it was taken apart, soaked in carb clearer, welch plug removed, old packing washers picked out, etc etc?? the boss or main jet gasket should keep the bowl from seating on its gasket until you tighten the bowl screws.

 

[59 Fatty]

Yes, I found the problem!! Thanks for all of your comments and suggestions. The problem was the bottom plug wire was not transferring current. I redid the end and checked again with gap spark tester. nice blue spark this time. All back together except cowl and face plate. BUT YEA!!!

 

[59 Fatty]

Here is a link to the video, I hope this works, I don't know what I'M DOING WRONG...