4 HP Evinrude Missing when warm

[Snowdrggn]

I have a 1976 Evinrude 4hp Weedless ( mod# 4606M) When it is cold it starts easily and runs well. Once it warms up, #2 cylinder quits firing completely. I have replaced the plug wires, checked the coils with a "Merctronic" (ignition tester) and both were good. The points are in good condition and correctly gapped. Is it possible that I have a bad coil on #2 that is not showing up on the tester? Any input or ideas would be greatly appreciated.....<br /><br />Thank you in advance.

 

[petrolhead]

Re: 4 HP Evinrude Missing when warm

It's quite likely that the coil insulation is breaking down under load, swap the coils around and see if that makes any difference.<br />What do the coils look like, old and cracked cases, or new? They are very cheap to replace if you need to.

 

[Snowdrggn]

Re: 4 HP Evinrude Missing when warm

The coils seem fine visually, and tested on the tester fine, with no errant secondary voltage evident. They both appear relatively new, with no cracks in the insulation. One of them was set too close to the flywheel at one time and shows signs of being in contact with it, but that is not the the one that is firing the cylinder that is causing trouble....

 

[petrolhead]

Re: 4 HP Evinrude Missing when warm

Swapping them should tell you straight away if one is defective.

 

[Chinewalker]

Re: 4 HP Evinrude Missing when warm

Have you replaced the condensers? <br />- Scott

 

[petrolhead]

Re: 4 HP Evinrude Missing when warm

I considered condensers, but in my experience they either work or they don't, never had an "iffy" condenser that worked intermittently, but it may be worth swapping those over first.

 

[Chinewalker]

Re: 4 HP Evinrude Missing when warm

Hi Petrolhead,<br /> We had a bugger of a time with the Phelon (Failin') condensers in the old Mercury Mark 20Hs as the original condensers weren't very robust. You'd get the motor running and it would sound alright until you were about halfway down the course and it would start skipping like someone taking the needle off a record and dropping it back on again. Finally got around it by using OMC condensers in them...<br />- Scott

 

[Snowdrggn]

Re: 4 HP Evinrude Missing when warm

I just picked up a new set of points and condensers. If that doesn't alleviate the issue, I'll put the coils back on the tester and put the heat to them while under test to see if one breaks down during an "extended" test....<br />The irony of this whole thing is that at the moment I have no use for this little motor, but I don't like to get beat on things like this....<br />Back to the garage then off to stir the barrel some more )

 

[Snowdrggn]

Re: 4 HP Evinrude Missing when warm

I put in the new points and condensers, stuck the motor in the barrel, all seemed fine. After leaving it run for about an hour the miss returned. One coil was stone dead and stayed that way, I was able to to catch it on the tester this round. I replaced both as I want reliability in any engine that I have around. It was kind of an expensive repair as by the time I got this far the whole ignition was replaced except the plate!<br />Oh well, maybe it will be reliable for another 28 years? I am going to decarbon it as it has probably not been done, it does run sweet though at this point in time...<br />Thank you to those that offered ideas...

 

[petrolhead]

Re: 4 HP Evinrude Missing when warm

It shouldn't have been that expensive a repair, 2 new coils, points and condensors for my Johnson 18 were less than $50, I'd call that pretty reasonable.

 

[Snowdrggn]

Re: 4 HP Evinrude Missing when warm

Petrolhead, I'm in western Canada, the prices must be higher here. <br />Coils: $36.25 ea.<br />Tune up kit: $28.36<br />Plug wire: $4.00<br />Boot Kits: $4.40 ea.<br />Plus 14.5% taxes<br /><br />I was'nt saying that it was an extreme amount to spend, just that it ended up being a complete ignition replacement by the time I won the battle <br /><br />Cheers.

 

[petrolhead]

Re: 4 HP Evinrude Missing when warm

At least it's done now though, with care it will last for many more years. I decarbed all my older motors and the difference was quite noticeable, especially the little Lightwin which suddenly ran like a new motor!