point gap setting on 28hp 1964 johnson rx-12

[fast_eddie]

Anybody know what the correct gap setting for the ignition points would be on a 1964 28hp johnson rx-12.

 

[fast_eddie]

Re: point gap setting on 28hp 1964 johnson rx-12

From what I have read this motor is cousins with the 1963 rx-11 and 1962 rx-10 johnson seahorse motors. I don't know if that helps. Would like to check to see if they are gapped correctly on mine. Misfires on a cylinder and coughs at high rpms only.

 

[JB]

Re: point gap setting on 28hp 1964 johnson rx-12

Set points at .020", eddie.

 

[fast_eddie]

Re: point gap setting on 28hp 1964 johnson rx-12

Ok now that I know that. Is thier any particular torque spec for the flywheel bolt as I don't want to shear the flywheel pin. I have a foot pound torque wrench that I plan on using to tighten the flywheel.

 

[tashasdaddy]

Re: point gap setting on 28hp 1964 johnson rx-12

60-65 ft lbs.

 

[F_R]

Re: point gap setting on 28hp 1964 johnson rx-12

I suspect that is incorrect. Here is the for-sure way to know:

If the nut takes a 7/8" wrench, it is 60-65 ft/lbs
If the nut takes a 1-1/16" wrench it is 100-105 ft/lbs

 

[JB]

Re: point gap setting on 28hp 1964 johnson rx-12

Pretty sure to be a 7/8" nut on a RX-12, F R. I think Daddy is right on.

 

[fast_eddie]

Re: point gap setting on 28hp 1964 johnson rx-12

Actually it's a 1 and 1/16" nut on the flywheel. So then it would be 100 or so foot pounds then. Correct?

 

[6228SH]

Re: point gap setting on 28hp 1964 johnson rx-12

my 62 28 horse has 1 1/16" nut and specs for it are 105 lbs if that helps.

 

[JB]

Re: point gap setting on 28hp 1964 johnson rx-12

My mistake. Learn something new every day.

My apologies, eddie and F R.

 

[Molaker]

Re: point gap setting on 28hp 1964 johnson rx-12

A silly little question, but just how do the pros hold the flywheel while torquing to 100 ft/lbs or so?

 

[fast_eddie]

Re: point gap setting on 28hp 1964 johnson rx-12

I just jammed a flat head screwdriver between the teeth of the starter and the flywheel and that worked for me. Didn't seem to hurt the teeth at all. I think the pro's probably use what they call a strap wrench. It would wrap around the flywheel and tighten down to hold it from turning while they tighten the flywheel nut.

here is a page for a strap wrench for tecumseh flywheels. Don't know if this would work for my app. but you get the idea.

http://www.manddsmallengine.com/tecumseh/tools/670305.html

Didn't get a chance to take the pontoon out after reassembly. One of the points was set at .017 but I don't think that would cause a miss at high rpm. Anybody else have an idea what could cause this. Plugs are new, and even tried a champion j6c in top cylinder to see if hotter spark would resolve the miss. It didn't. Maybe valves are carboned up or somthing. I just don't know what to try next. Carb rebuild maybe, I would not think it's the carb though as bottom cylynder looks to run fine, and she idles good.

 

[F_R]

Re: point gap setting on 28hp 1964 johnson rx-12

Being a pro, I can admit that I too stick a big screwdriver in the teeth. But don't tell anybody. However, on a non-electric start one you have to use a strap wrench. I made my own about 40 years ago.

It doesn't have valves, so cross that off your list. Carb being set too rich will make it "four cycle", but remember the carb feeds both cylinders so it can't just affect one.

A holed fuel pump diaphragm will make one cylinder rich.

 

[tashasdaddy]

Re: point gap setting on 28hp 1964 johnson rx-12

thanks Frank for correcting us.

 

[Molaker]

Re: point gap setting on 28hp 1964 johnson rx-12

Being a pro, I can admit that I too stick a big screwdriver in the teeth.

Well, I'm glad to learn the "professional" way to do it. I was afraid I might bugger the teeth or something. Now maybe I can relax and tear something up.

 

[fast_eddie]

Re: point gap setting on 28hp 1964 johnson rx-12

Well I figured out what was wrong. The top cylinder is occasionally loosing spark. I used an automotive timing light on it. I have decided that I am going to do a full ignition replacement. I talked with my grandpa who owned this motor for 20 years before me, and he said he has never done anything with the points or coils. I think it's time for a total tune up including new ignition coils, point's condensors and plug wires. I have already done this to her and she runs a hole lot better.