'66 johnson Goes for 30 minutes no restart

'66 johnson (v4sl-180) Goes good for 30 minutes .. lil hesitation when you hit the throttle. nothing major or real concern (carbs been cleaned) After 30 or so minutes it runs AWFUL for 15-30 seconds dies and yep dead in the water. Cant get it to restart . dunno how long it takes, But next day go out and it cranks on first Start. Ideas? New water pump lots of water flow

Re: '66 johnson Goes for 30 minutes no restart

Run it till it quits and then check for spark, if you don't have spark you know where your problem lies.

Re: '66 johnson Goes for 30 minutes no restart

fishnfan said:

'66 johnson (v4sl-180) Goes good for 30 minutes .. lil hesitation when you hit the throttle. nothing major or real concern (carbs been cleaned) After 30 or so minutes it runs AWFUL for 15-30 seconds dies and yep dead in the water. Cant get it to restart . dunno how long it takes, But next day go out and it cranks on first Start. Ideas? New water pump lots of water flow

Click to expand...

Good flow, but is the head getting hot?

Re: '66 johnson Goes for 30 minutes no restart

Running it until it dies and checking for spark will just leave me stuck in the water again. (which paddling back to boat dock with at least 2000ft no wake is not alot of fun ) what would cause no spark so i can try to diagnose w/o getting stuck in water again? i had the idea of not getting spark , and bit the bullet as i didnt have anything on the water to test with so just held on and got a jolt, just to know it was getting some spark.
As for the head getting hot the test light for temp came on few weeks ago.. and impellor was replaced. Its not coming on anymore so assume its not getting hot. Motor is touchable for a couple of seconds

Re: '66 johnson Goes for 30 minutes no restart

Since it did get overheated recently, it would be a good idea to run a compression check on all of the cylinders. If you can hold your fingers on the head for a good 3 seconds, you're probably OK.

Re: '66 johnson Goes for 30 minutes no restart

any suggestions on to do if i did take it out on the water again and got stuck to paddle my way back, if it wasnt getting fire or proper spark. i know its getting a lil cause like i said i got a jolt testing it by hand. but where to start if not proper or correct spark? simplest cheapest ofc first. Not to knowledgable on boats so i try to read as many posts on here i can.
on a side note if i was getting good water flow what would cause overheating.? besides being too lean? Its on a 1966 Larson so not to confident of the warning lights.

Re: '66 johnson Goes for 30 minutes no restart

It is a 90% safe bet that you have a bad coil, breaking down as it heats up. Part number 580243. If you think you got a shock before, wait till you get the price on the coil.

I might work to take the hood off and leave it sit out in the hot sun for a couple of hours, then test for a good spark. Beats paddleing.

Re: '66 johnson Goes for 30 minutes no restart

ouch $200 .. ive read somewhere on this forum that an automobile coil will replace some also as theyre cheaper (cost wise) if so what to look for etc..? any truth in this?
also is this the same as id be buying from a local dealer or is this a what ya get what you pay for item? http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=370230159298&viewitem=

Re: '66 johnson Goes for 30 minutes no restart

Ok some updates on tests.
I have 110 lbs pressure on all four cylinders.
Spark test i have blue spark to 3/16" on the tester
1/4" is intermittent and 5/16" no spark.
Spark is suppose to be 7/16"? what would cause low distance?
bought a condensor as it was in the local shop instock so plan on replacing it
They said that might be a cheap fix.
Any tips b4 or thoughts b4 i try that?

also, looking from the rear to front the right side of the motor seems to be getting hotter than the left. Any ideas on that?

edit: trying to hold a little bit of pressure on timing belt to break the nut loose i broke the belt. so guess it was pretty dried out. Arghs another $50.

Re: '66 johnson Goes for 30 minutes no restart

Just checking to see if any new ideas or thoughts .
thanks

Re: '66 johnson Goes for 30 minutes no restart

No new ideas - just the same one F_R suggested before. Probably the coil. Weak spark confirms it. The one you saw on Ebay is the correct one.