missing at idle, 1963 18hp fast twin

[hawk232]

I have a 1963 evinrude fastwin 18hp and recently had alot of problems, most of which came back to water in the gas. Through all of that I replaced just about everything (carb kit, points, condensers, coils, wires and plugs). Now i am having issues where it misses at idle and will eventually die. I have re set the points several times and sometimes it seems to help, others it doesnt. It only acts up at idle though. If i speed up to even fast idle it clears up. Any ideas?

 

[kfa4303]

Re: missing at idle, 1963 18hp fast twin

How does it run at higer rpms? What did you set the points to? Should be .020". If it's ok at higher rpms, I would think that you just need to adjust your lo speed needle a bit to dial in a nice idle. Here's a great link from the forums that can help with setting up your carb. You may also want to check the idle set screw on the side of the motor at the base of the the vertical throttle tower and it can be adjust it as needed. Screwing it in advances the timing and raises the rpms, while backing out the screw lowers the rpms. Finding a balance between the lo speed needle and the idle set screw is key to getting a nice idle. Hope these hlep some.


http://forums.iboats.com/showthread.php?t=167352



http://forums.iboats.com/showthread.php?t=167352

 

[hawk232]

Re: missing at idle, 1963 18hp fast twin

How does it run at higer rpms? What did you set the points to? Should be .020". If it's ok at higher rpms, I would think that you just need to adjust your lo speed needle a bit to dial in a nice idle. Here's a great link from the forums that can help with setting up your carb. You may also want to check the idle set screw on the side of the motor at the base of the the vertical throttle tower and it can be adjust it as needed. Screwing it in advances the timing and raises the rpms, while backing out the screw lowers the rpms. Finding a balance between the lo speed needle and the idle set screw is key to getting a nice idle. Hope these hlep some.


http://forums.iboats.com/showthread.php?t=167352



http://forums.iboats.com/showthread.php?t=167352

yep, points at .020. I have played with the idle mixture screw to no avail. I have not, however, heard of the idle screw on the side of the motor. I will check it out and see if it effects it. I need to see what cylinder its missing on, its just too cold outside right now to mess with!

Also, when i first installed the new coils I had them aligned wrong. It was ran for a little while until I became aware of the problem. Now one of the tabs (that you line up with the baseplate) is sort of flared. In other words, the metal tabs consist of a bunch of plates (seemingly) laminated together, now they are "flared" apart from one another. I wouldnt imagine that this could be the problem, but I have been wrong before... one time back in 1999... well thats a story for another day!!

 

[levi_tsk]

Re: missing at idle, 1963 18hp fast twin

if you damage a coil in anyway its toast if theres a crack in the insulation or or those plates are messed up that is the problem those plates are your primary winging and its where the coil gets its initial power before it ramps it up on the secondary winding and sends it to the plug
youd be surprised at how well one of these engines wil run on one cylinder if kept above a certain rpm

check your spark at both plugs and make sure before you mess with anything else

 

[kfa4303]

Re: missing at idle, 1963 18hp fast twin

If you're missing/not firing on one sylinder that can certainly explain the rough idle. Here's a pic of what and ideal magneto should look like. It may help some. If you have some pics of yours they may help too. I would recommend a little $10 s'plug tester from the auto parts store. That way you can be sure you're getting a good strong spark. The gap testers are best, if you can find them. The spark should be able to jump a 7/16" gap with a nice, snappy blue spark. You might want to double check that the correct s'plu wire is going to the correct cylinder. The top (#1) cylinder s'plug wire probably had a small metal clip/ring on it indicating that it should go to the top cylinder. Sometimes when folks change the s'plug wires they forget to put the ring back on the correct wire, if at all. Just a few thoughts. Any way, here's a pic of a nice magento and the idle set screw is was talking about. Hope it helps.

 

[levi_tsk]

Re: missing at idle, 1963 18hp fast twin

nice pics karl i wish mine would have come out that good im stealing your magneto pic btw wish i had itthe other day i wired it up backwards and had no spark

hawk notice how kfa has his wires routed here too they MUST be routed this way or the WILL hang on the flywheel and or get rubbed raw by it and short out a cylinder notice how the green wire goes underneath
and to the set of points to the right and the ground is mounted to the coil anything any different than what kfa has there and your begging for trouble ...
ps if you mess up a wire to the coil you might as well replace the whole unit

 

[mudlake1]

Re: missing at idle, 1963 18hp fast twin

I have two very similar motor.
Mine are 1961 johnsons.One idles perfect and the other is very good.
One thing to make sure is to Have a ground wire from your timing plate which holds the coils and points to the engine block near the spark plugs.

 

[hawk232]

Re: missing at idle, 1963 18hp fast twin

I did know about that screw afterall....

as for the wire routing... i learned that one the hard way. I have them routed a way now that they no longer rub. I still have my old coils that I believe are still good, I may swap them out to see if my coils are messed up because of rubbing the flywheel. Thanks for the advice everyone, I will get back after I have done a little work.

 

[levi_tsk]

Re: missing at idle, 1963 18hp fast twin

ok good luck

 

[kfa4303]

Re: missing at idle, 1963 18hp fast twin

hawk, make sure the black wires that go under/behind the coils from the pints to the push button kill switch that are tucked out of the way nicely too. I just changed them when I put in a universal dead man's switch and I didn't quite tuck them away well enough and it caused my coils to line up poorly such they hit the fly wheel as you described. I just loosened the coils and took extra care to tuck the wires away. When I tightened the coils back down they were good to go. unfortunatley, you can't really see them in the pic, but they're wired to the points along with the coil and condenser and run to the kil switch on the face of the motor. keep us posted.

 

[samo_ott]

Re: missing at idle, 1963 18hp fast twin

I have two very similar motor.
Mine are 1961 johnsons.One idles perfect and the other is very good.
One thing to make sure is to Have a ground wire from your timing plate which holds the coils and points to the engine block near the spark plugs.

Hmmm. That's an interesting idea. Grounding the ignition plate. It was not originally done and I have never done it but I could see it helping in certain circumstances.

 

[steelespike]

Re: missing at idle, 1963 18hp fast twin

If the armature is damaged you probably could replace just the armature with the one from the old coil.