1995 Johnson 115 hp Starting Problems

[Tigger]

I just had this motor rebuit a month ago; carbs included. When cold starting it sometimes backfires and takes several cranks to start. After its started, it runs great, idles fine and restarts quickly with no problem; If I let it sit 10 minutes or so, same problem. I running 25:1 oil mixture for break-in and mechanic says give it some time, get on a 50:1 mixture and things should improve. Any thoughts? The motor is still under warranty(2 months remaining). Should I push the issue? I don't want to break down in the middle on nowhere if this can be avoided.<br /><br />Thanks<br /><br />Darren

 

[Fouled Plug]

Re: 1995 Johnson 115 hp Starting Problems

25:1 is a fairly rich mixture, and the spark plugs don't like it a lot, especially at low speeds. I would take your wrench's advice, and try running it again after careful break in on that first tank. And do it before the warranty expires!

 

[Dhadley]

Re: 1995 Johnson 115 hp Starting Problems

What spark plugs and fuel?

 

[Tigger]

Re: 1995 Johnson 115 hp Starting Problems

Thanks FoulPlug and Dhadley. The plugs are Champions QL77JC4 and I'm using Chevron medium grade fuel; I also added OMC 2+4 fuel conditioner. I don't think it is the timing since it does not do it all the time...right assumption? Maybe I should just wait untill I get to a 50:1 mxture. <br /><br />thanks again<br /><br />Darren

 

[Tigger]

Re: 1995 Johnson 115 hp Starting Problems

What is the acceptable break-in period for new/rebuilt motor. My mechanic wants me to run two tanks at 25:1 fuel/oil ratio. I have a 40 gal fuel tank? Is this over-kill or CYA on his part?

 

[Fouled Plug]

Re: 1995 Johnson 115 hp Starting Problems

The last Merc manual I saw recommended 25:1 for the first tank, then regular mix. This was for a 2001 15hp with a 6 gallon tank. I would think 40 gallons would be sufficient for your application, but your mechanic must know his stuff. Do your plugs look pretty carboned up? I don't think I'd get too concerned at this point. Fudgy plugs don't like to fire as well as clean ones!