1980 140 Evinrude running cold

[Taz466]

Hey folks, Great forumn. <br />Since we have houses floating in the lakes here in Texas, I can't test my engine. I thought I would pick some brains out there. I have a 1980 140 Evirude that was completely rebuilt last year and have a few problems. Rough idle, smoking too much at idle, oily plugs and low holeshot power. Runs great at speed. The carbs were jetted and synced by a pro, BUT, a buddy of mine suggested clipping the thermostats when we were building the engine. My guess is it was a bad move. Head temps only get to about 115 on all cylinders. Since the thermostats are such a pain in the $#$% to change I left them that way for the 1st season. Now I'm in the process of putting stock thermos in. My questions are:<br />What are the symptoms of a cold running engine? I can see the smoking at idle and oily plugs being one which then causes the rough idle. What is the normal running temps? (My manual is still in a box from a move) Anyone have other suggestions to try? BTW, all parts on the engine are new. <br />Thanks for the help.

 

[Dhadley]

Re: 1980 140 Evinrude running cold

Clipping the stats is OK in warm water. I'd look more at timing, oil ratio, what brand (and type) spark plugs, fuel and what jets were replaced. You also said it runs great at top end but forgot to mention top RPM's.<br /><br />Be specific!

 

[Taz466]

Re: 1980 140 Evinrude running cold

Thanks for the reply dhadley,<br />Top RPM is unknown. The engine is bored 30 over, balanced, ported and polished and good (I'm told) to 8500. I haven't had the engine over 6000, the boat gets too light. It goes from 2000 to 6000 in about 4 secs. Oil is Penzoil TCW3, with 93 octane fuel in 50/1. I'm experimenting with 70/1 and keeping the RPM's down. So far no luck. High speed jets are stock (.030) The low speed were changed from stock and I don't know what they are now. I'm running the stock plugs (Champion QL77JC4) gaped at 30. I have a hotter set to try next. Timing is standard at 4 deg.<br />Thanks for your help.

 

[fireman 757]

Re: 1980 140 Evinrude running cold

It is not a good idea to run hotter than suggested plugs. I also wouldn't thin my mixture. Stay at 50:1. If you lean your mixture and run hotter plugs you are asking for some serious head problems you don't need. Sounds like your boat is overpowered and too torqued up to be safe.

 

[fireman 757]

Re: 1980 140 Evinrude running cold

It is not a good idea to run hotter than suggested plugs. I also wouldn't thin my mixture. Stay at 50:1. If you lean your mixture and run hotter plugs you are asking for some serious head problems you don't need. Sounds like your boat is overpowered and too torqued up to be safe.

 

[Dhadley]

Re: 1980 140 Evinrude running cold

If your timing is set at 4 degrees your holeshot will be horrible. I find it hard to believe you get anywhere close to 6000 RPM with only 4 degrees and .030 high speed jets. And you say youre looking for 8500?<br /><br />There has to be more to this story. Tell us more!

 

[Taz466]

Re: 1980 140 Evinrude running cold

Well, after building the motor, I wanted everything to be stock settings for break in. This is the first motor I have built, so I wanted to start out carefull. The motor is on a 16 ft Glastron/Carlson with a jack plate running a 19 pitch prop. After break in we opened it up and it was fast enough. It hit about 65 at 6000 with full fuel and 2 people. It was VERY light in the water. I decided not to advance timing or increase the high speed jets. BTW, I'm not looking for 8500 RPM, I was told the motor will stay together at 8500. Also isn't 4 degrees standard timing at idle? I have looked everywhere for my manual and it is MIA.<br />Thanks

 

[Dhadley]

Re: 1980 140 Evinrude running cold

I would not change a thing! With a 19" prop at 6000 RPM theoretical speed is just under 55. You have not only conquered the slip factor, you got it going the other way.<br /><br />I don't worry a whole lot about idle timing but we are concerned about WOT timing. Your motor is supposed to be at 26-28 degrees. However, since you have to run high test fuel you must be running higher than stock compression. I would stick with what your machinist or whoever recommends since he is the one who blueprinted your motor.<br /><br />I am curious about how you are getting away with .030 high speed jets.<br /><br />The G/C's are cool rides. Have fun!