1978 evinrude Spark issues

[kevin11mic]

I have had this motor for about 6 months and have been out in it at least 50 times. The problem originally started when i was on my first hunting trip for opening morning of teal season. We were about half way to the blind and it just died. So i wore on the starter for about five minutes and it didn't even try to start. so i pulled the plugs and they were fouled with oil so i cleaned them off and did a spark test by holding it to the ground and it was real week but it had spark. When i finally got home i threw some new plugs in it and it fired right up on the hose. I ran some evinrude johnson engine tuner through it and took it out again and it did it again...please help cuz its blowing my mind

 

[kevin11mic]

Re: 1978 evinrude Spark issues

By the way its a 25 hp tiller

 

[tashasdaddy]

Re: 1978 evinrude Spark issues

running tuner thru it was a waste. do a proper spark and compression test, if good disassemble, clean, and reassemble the carb with a carb kit. spraying a 2 stroke carb is a waste. the engine tune is for burning carbon out of the inside of the engine.

read the TOP SECRET FILE. great knowledge assembled there.

 

[kevin11mic]

Re: 1978 evinrude Spark issues

i used the engine tuner do burn the carbon out because i called the local shop and he asked me if there was sludge running down the engine when running on the hose and there was so i used the tuner. he also told me that the thermostat could be stuck open causing the fouled plugs. i did a carb kit on the engine when i bought it

 

[OptsyEagle]

Re: 1978 evinrude Spark issues

The main reasons you foul spark plugs is if you are running too rich or you are running too cold. The steps I would take are:

1) Ensure you are using the correct plugs: Should be Champion QL77JC4 gapped at 0.030"
2) Ensure that your slow speed adjust on your carb. is set right. Here's how you do it.

http://forums.iboats.com/showthread.php?t=167352

3) Ensure that your ignition system is putting out a strong spark able to jump a 7/16" gap.

4) Ensure that your T-stat is operating properly - can be tested by putting it in a pot of water and heating it up on the stove. It should start to open at around 140F and be completely open at around 150F.

I would also want to know what the compression is on the motor

When you fix the fouling problem, if that is what it is, you should run a decarb through it like you may have done, to get out all that carbon from your cylinders. By the way, sludge comes out of all 2 stroke motors when you run them in a barrel.

 

[kevin11mic]

Re: 1978 evinrude Spark issues

Just ordered a new thermostat...pulled it and it was stuck open wouldnt move when i put it in the hot water... im guessing it was causing it to run cold...guy b4 me did compression check and both cylinders were arround 120 if thermostat dosent fix il do the compression check again.

 

[kevin11mic]

Re: 1978 evinrude Spark issues

i installed the new thermostat and took it out. it seamed to do fine i ran it for over an hour. time will tell.

 

[OptsyEagle]

Re: 1978 evinrude Spark issues

That's great. Wouldn't hurt to run a Seafoam decarb on the motor soon. If carbon was getting on the plugs to make them foul you can be sure it was getting on your cylinders and piston rings.

 

[kevin11mic]

Re: 1978 evinrude Spark issues

I will do a de carb would you recomend sea foam or evinrude johnson engine tuner?

 

[OptsyEagle]

Re: 1978 evinrude Spark issues

I like Seafoam better. Try to get the deep creep arosol version, or put some regular seafoam in a spray bottle, so that you can spray it right into the carb at a fast idle. Do that quite a few times, then shut it down, tilt up the motor, remove the spark plugs and spray a good amount into the cylinders and rotate the flywheel to mix it in. Lower the unit and replace the plugs, do not tighten at this point since the motor should still be a little hot. Wait about 1 hour and tighten up the spark plugs, fire up the motor and I would spray a few more shots into the carb again.

Take the motor out and run it hard for 10 to 15 minutes to blow out the crud and call it a good decarb. Some would say to change the spark plugs after this but with new plugs, they will probably be fine. My plugs have survived every decarb process I have ever put my motor through.

If you search decarb on this site they use a "seafoam in the gas" method. My problem with that method is I always mix up too much gas and either I wait for the time it takes to burn it through or use this other method. It is my preference, but both methods would work fine.

 

[kevin11mic]

Re: 1978 evinrude Spark issues

took the boat out today to build duckblinds and after about 2 hours it did the same thing it was doing before. It just died. so i pulled the plugs out and they were fouled up so i did a spark test with a new plug and there was very little to no spark. Looks like i might have an ignition problem of some sort. Its got to be something simple because it runs like a top when it is fresh.

 

[OptsyEagle]

Re: 1978 evinrude Spark issues

Check the spark with a spark tester. It should just a 7/16" gap.

 

[kevin11mic]

Re: 1978 evinrude Spark issues

i took it to the local shop... he is gonna troubleshoot it for me and figure out exactly what is wrong with it...when i know il post it for further refrence

 

[imperial184]

Re: 1978 evinrude Spark issues

hi i dont know much about boats. just purchased my first one today and had the same spark problem. replaced a coil and didnt help, here the points were dirty cleaned em up with sand paper and it worked great. I have a 3.7 mercruiser. hope i could help