running on one cylinder.....when hot

[Tin-man]

Just got my new steering shaft installed yesterday. Big thanks to Lloyd for the part donation.

On to the next issue. The past few times I have been out, the sled runs great for about 30 mins. Then its like there is no power and its running on one cylinder. I am thinking it is the CDI unit or the coil or both.

And ideas?

[drifterdude440]

My Drifter 440 has done this same thing to me lately and I'm still narrowing down the problem.  I've noticed it happens when getting up to higher speeds.  Check the resistances and voltage outputs of the coils, both internal and external (ignition).  I noticed when mine was running ok I got 32 Vac on one of the internal coils, and about 26 Vac when it wasn't running at all.  I'd have to dig up my book to check the official specs / test of each.

[Lloyd (ljm)]

   


    Dustin

  I have had spark plugs do that. Work great cold but not work warm.

 It could be a number of things that are cheaper than coils or CDI's

 Check the grounds, spark plug boots can also do that.

 CDI's and coils are more apt to affect both cylinders (not saying that it can't be either of them)

 I would check everything else out before I replaced CDI or coil.

 Lloyd

[kawhead]

crank seals have been replaced?

[Lloyd (ljm)]

 Yes I helped Dustin do the crank seals last fall

[kawhead]

imo....not cdi box or internal coils, maybe ex. coil, have you replaced the spark plug wire ends yet? i've seen lots of issues there,esp. 1980 and up,the had a copper wire end that was pretty fragile

[jimvw57]

sounds like it is electrical. I'd go with spark coil first.

[Checkmarks]

When you know you are running on just one cylinder, swap plugs, then swap coils (if more than one) and it helps to see if this issue is even in the electrical system.  The problem could be in the carburetors if you have more than one. 

What sled do you have?

[Tin-man]

Issue still persists.

I ordered a new CDI and external coil and caps today from Royal. I will post my results after install.

[Lloyd (ljm)]

Dustin

 I would replace the parts one at a time. That way you know what was wrong.

 Lloyd

[Tin-man]

Dustin

 I would replace the parts one at a time. That way you know what was wrong.

 Lloyd

I replaced my CDI, this wasn't the issue. I replaced my external coil, and the sled ran great! I was out for 40 mins, and no issues. Next thing to tackle is the brake.