1972 Johnson 25hp runs well for 5 minutes and starts missing

[60sboater]

I just got his off of CL yesterday,model 25R72R,sn E3601773. I have it in a 55 gal barrel and it runs fine for a few minutes then starts chuffing/misfiring and will eventually get to the point where it will die. It has Champion J8Cs in it. I'm running 50:1 with some E-10 that is about a month old. Is J8C the right plug?



I've been reading some posts last night and today. Any help with this will be much appreciated.

 

[60sboater]

I'll reply to my own topic. I put in new J4Cs and ran some fresh Shell 89/oil and it ran for 30 minutes without the misfiring. This has electric start with no switch so I've been pulling. The idle seems high but I don't have a tach. It pumps water well.

 

[bonz_d]

Welcome to the iboats forum! Great find there with that 25hp. Now for the true test, get it on the water!

 

[60sboater]

Thanks,nice to be here. I'll take the black 9.8 off and try this one soon,Lord willin'. The electric start was apparently added-on. Nice looking rig you have;I have a 14' Grumman...another CL find from last year. It had a 4hp Coleman (Parsun) on back.

 

[bonz_d]

That 25hp should push that Grumman very well.

Thanks for the nice comment. Boats seems to be breeding. Now at 4. I hate graislist, too many deals. The latest is a 1984 14' Sea Nymph FM144. Picture and post here. http://forums.iboats.com/forum/gene...e-topics/9956461-another-one-fallowed-me-home