engine seems to run rough once warmed up

[JUSS10 250]

ok so i've been reading through a lot of the threads on rough running engines. i have a rebuilt 181 in my 603 i recently picked up. i have rebuilt the carb with a kohler carb kit and set the float level according to the manual. i thought it had a blown head gasket as i was seeing residue come out between the head and the block. sure enough so i got a new head gasket and torqued it all to speck. seemed to run better. well i took it out yesterday morning to do some field work with my cousin and it ran great for a while then the longer we were out there, the worse it ran. it would want to die at higher RPM finally to the point it just wouldn't run off idle. we stopped to take a break and a few minutes later we hopped back on but it just wouldn't run good. finally got it to start and then we couldn't get it off idle. it would stutter then the governor would slam the throttle wide open and die. i tried running it by controlling the throttle myself with the hood off and it still wanted to die unless i was really really careful to open the throttle. points are clean (hit them with a point file) they are gapped right. cleaned the head when i replaced the head gasket. i found out it was bored 20 thou over. later that night after having it sit for a while it fired right up and i could run it without any hesitation. any thoughts? thanks

Justin

[rmaynard 15,964]

See how it runs with the gas cap loose. Seems to be a lot of clogged cap vents going around these days.

Bob

[JUSS10 250]

tried that as well.... :thumbs:

[TT-(Moderator) 1,147]

Try another condenser.

[JUSS10 250]

thanks TT I am going to run to napa today and get one ordered. quick question which one do i need? on their site they show one with a wire attached and one that has a screw where you can add the wire. does it matter which one?

[JUSS10 250]

OR

[TT-(Moderator) 1,147]

The one with the "pigtail" is normally found on the engines with battery ignition.

The other one you have pictured is used on many of the magneto ignition engines with the condensers not mounted under the flywheel.

They do have different capacitance values, so you should match them to the corresponding ignition type.

[JUSS10 250]

ok well i need a magneto one. so would that be the last one i showed?

[TT-(Moderator) 1,147]

ok well i need a magneto one. so would that be the last one i showed?

Perhaps.

Were you able to locate the current condenser?

[JUSS10 250]

yes i located the old one and though everything else on the motor looks like it had only 50 hours on it (thats what the PO told me) the stuff under the flywheel didn't look as nice. i ordered a new condenser from napa as well as a new set of points (even though these looked fine) but i have some new questions. and i think the pictures explain it all. is the magneto supposed to look this, well, bad? its got all these cracks on it and there is a wire coming out the top that isn't shielded and just wondering what all this is suppose to look like and if there is any maintenance that needs to be done while i have this all apart.

[Roger from southern Iowa 1]

I think you found your problem.

Magneto is plumb ugly :thumbs:

[sorekiwi 761]

I'd also polish up that taper on the end of the crank (and the matching bore in the flywheel), there's no way the flywheel will seat well on that.

[WH nut 553]

That doesnt look to bad, its just weathered. The cracking is the epoxy over the coils. If you dont see bare wires you should be ok. The whole set up needs a good cleaning. The rotor on the crank shaft should be shinny as well as the metal ends on the coil, sand paper them clean and make sure the insulation on all the wires are good. Replace the condensor while you are there. After its allcleaned up you can check the spark before you install the flywheel. If you are brave enough just hole the plug wire and rotar the crank by hand. You should feel a little spark, nothing that will light you up since you will be spinning it so slow. If that all passes you are good to go. If not look at a new coil.

[JUSS10 250]

what about that wire in the third pic. is that supposed to be exposed like that?

[WH nut 553]

Thats ok, its just the goil ground

[WH nut 553]

Wait, it that wire goes to the condensor no tape it up, if it goes to a ground its ok, had to tell in the picture

[JUSS10 250]

pretty sure its a ground wire. thanks for all the help :thumbs:

[WH nut 553]

Cool, You should be all set, let us know

[JUSS10 250]

well got it all back together last week and wow what a difference. fires on the first pull. mowed the yard with it the other day and everything was fine for a while but then it seemed to bog while mowing uphill. like the governor was out of adjustment but it worked fine for the first 15 minutes going up and down the hill. it was a little hard to start after turning it off as well... not as bad as it was before but still a little hard. should i look into a new magneto or search else where for the issue? i'm going to double check the governor again and see if that is off i might double check the carb as well. i never tuned it "under load". the driveway could use a dragging. maybe I'll put it in first gear with the spike drag then walk next to it while tuning the high end needle.

thanks to all who helped remedy most of the problem :thumbs:

[WH nut 553]

Yes double check the carb adustment and maybe check the tank where the fitting goes in to make sure it isnt all rusted up and restricting the fuel flow. I wouldnt think its the coil just yet

[Ken B 3,166]

Justin replace the coil. Back in the 1950's and the 60's the plastic insulatiing the coil was of an unstable material. They would shrink with age or heat causing the coils to crack or split letting moisture into the windings. This causes the mag too produce an inconsistant spark. Alot of the time the coil will test out ok on the bench but once your motor warms up the spark becomes inconsistant.

I restore antique outboards from the 1950's and this is a very common problem with outboards of that time period. The coils all cracked. On a boat though you are usually a few miles from shore when things act up, so you don't skimp, you buy new coils. Trust me, I've been there and I know much better now. Never trust a cracked coil.

[JUSS10 250]

thanks Ken. thats kind of what i figured it would be. i will try and track a new one down. thanks for the tip :thumbs:

[JUSS10 250]

does anyone know the part number of the magneto or where i can find a replacement?

[TT-(Moderator) 1,147]

:thumbs:

http://www.wheelhorseforum.com/index.php?showtopic=20079

[rydogg 186]

Just wondering if you found a coil yet? I have one on a K181ET motor that I purchased in pieces so I cannot guarantee that the coil is still good but it looks good. It very inexpensive so it can't hurt to try it out. Let me know, I can get pictures if necessary.

Ryan