1970 4 hp evinrude

[joejoe]

When i am running the engine in a test tank, iam getting all kinds of black oil in the water. I have checked the lower end and it is not leaking where else could this oil looking substance be comming from?. Also the motor will run for short periods of time at wot and 1/2 throttle then just dies. i have put on a new fuel pump, water impellar, rebuilt the carb. what is going on with this motor. I just dont get it. All help appreciated. thx Joe

 

[JB]

Re: 1970 4 hp evinrude

Hi, Joe. That oil in the tank is unburned lubricant. Normal. One big reason why 4 strokes will dominate the future of outboards.<br /><br />Your problems still sound like carb or fuel supply problems. There is something wrong. That engine is normally as smooth as a sewing machine.<br /><br />Red sky at night. . . <br />JB

 

[joejoe]

Re: 1970 4 hp evinrude

JB, I will be doing a compression check with the motor cold today i will let you know what the cylinders read. It is the strangest thing i ever saw, the primer bulb stays firm, getting a large supply of fuel from the fuel pump to the carb, It really has me stumped! Getting a nice blue orange spark 1/2 " from ground. No matter where i set the low or high idle speed at it will not run right and idle down. I am also going to be putting on a new head gasket today as well, might as well it's a cheap part, sort of. I do note when the engine is running at wot and 1/2 throttle it smokes alot and smells real strong of unburned fuel. to rich of mixture is what i think, But if i try to lean it out 1/16 of a turn at a time it just dies. I am using 87 octane gas 50:1 mix. am i headed in the right direction here or what.Sorry for being so long winded.<br />thx Joe

 

[joejoe]

Re: 1970 4 hp evinrude

JB on my compression test uppper cylinder i get 75 psi<br />on the bottom cylinder 80 psi. Please read my post above also.<br />thx Joe

 

[JB]

Re: 1970 4 hp evinrude

Your compression is low, Joe, but you are headed in the right direction. <br /><br />Fire her up. Rev her to at least half throttle and spray a little water (yes, WATER) into the carb. If you get smoke, continue this until the smoke turns white. Then try another compression test.<br /><br />The water will cause carbon in the rings, combustion chamber and on the piston head to fracture and disintegrate, then be pumped out the exhaust as smoke. When it turns white, it is only steam.<br /><br />Good luck.<br />JB

 

[joejoe]

Re: 1970 4 hp evinrude

Thx JB i will give it a whirl Wednesday, and let you know how it all goes. thx Joe

 

[joejoe]

Re: 1970 4 hp evinrude

Hi, well JB I DONE WHAT YOU SUGGESTED TO DO. i AM KNOW GOING TO REPLACE THE HEAD GASKET. THIS AFTERNOON. DOES ANY BODY HAVE THE TORQUE SPECS ON TIS LITTLE MOTOR HANDY. Thx Joe<br />P.S. i will keep you posted J.B. ON IF IT WILL NOW IDLE AS SOON AS I GET THOSE TORQUE SPECS, THX AGAIN

 

[JB]

Re: 1970 4 hp evinrude

Hi, Joe. Torque the head screws to 5-7 lb-ft. Good luck and let us know what happens.<br /><br />Red sky at night. . . <br />JB

 

[joejoe]

Re: 1970 4 hp evinrude

HI, WELL i am ready to throw the motor in a lake, i assembeld the head back together with new head gasket torqued the bolts to 6 ft pounds. The motor started quite easily on it after 2 pulls, i then ran it up to appx 3000 rpm and sprayed water in the carb as you had suggested ran it for 15 minutes until some white smoke came out, i'd say not alot though. Rechecked compression and now have 90 psi in the upper cylinder and 95 in the lower cylinder. Then i went to start it back up and will not restart on it's own, so i do the wd40 trick and it fires enough on that to get it going again. Then once it was going smoothly sort of i proceeded to try the rich and lean adjustments 1/16 turn at a time slow and high speed. and it starts to die out. so i quickly turn the high side back to a richer adjustment and it continues to run but " very rough". JB i AM READY TO CRATE THIS THING UP AND SHIP IT TO YOU IN TEXAS. ANY SUGGESTIONS AT THIS POINT?. Thx much Joe

 

[JB]

Re: 1970 4 hp evinrude

Well, you got the compression up where it should be, Joe, and balanced, too. You have made great progress. Now you need to get the carb adjusted correctly.<br /><br />Set the lo speed adjustment 1 1/4 turn out from the seat. Start her up and give her time to warm up. Now adjust the lo speed jet for a comfortable idle (around 700 rpm). You will probably be turning the control in (CW).<br /><br />The next adjustment must be made under load. Fire her up and bring to 3/4 throttle. Set the hi speed jet to get smooth running. (this should happen at between 1 and 1 1/2 turns out from the seat).) <br /><br />Good luck and let us know what happens.<br />Red sky at night. . . <br />JB

 

[joejoe]

Re: 1970 4 hp evinrude

off to the lake i go see what i can get her to do. will let ya know what happens in appx 1 hr. thx Joe

 

[joejoe]

Re: 1970 4 hp evinrude

WELL WELL A VERY BIG THANK-YOU THANK-YOU<br />SEA TRIALS WENT QUITE VERY WELL, I COULD ACTUALLY GET IT IDLE DOWN TO JUST A PUR LIKE A KITTEN AND THROTTLE UP VERY WELL TO 1/2, 3/4 AND WOT. IT DONE AWESOME. I'd like to THANK EVERYBODY INVOLVED IN HELPING ME GET THIS GOING, MAN JUST 2 POST AGO I WAS READY TO THROW IT IN THE CREEK. THESE FOLKS HERE ARE AWESOME !!!!! SHE DOES SMOKE A BIT BUT I GUESS I CAN LIVE WITH THAT FOR A 30 YEAR OL MOTOR. RUNNING 50 TO 1 87 OCTANE, COULD I TRY A LOWER MIX, SAY 40 TO 1 OR 32 TO 1 ? tHX YA ALL AND KEEP UP THE EXCELLENT BOARD HERE.

 

[motwerf]

Re: 1970 4 hp evinrude

I have a 1995 +- 6 hp that has low compression , 75 PSI on both cylinders. <br />I had it down to the bearings this spring as it had 60 PSI at that time and would not idle under load for more than 5 minutes, mostly less. <br /><br />On the advice of a couple of mechanics we did not replace the rings, just buffed the cylinder walls. (there was no obivious glazing and the rings and pistons were all above minimum specs.) this gave us the 15 PSI increase. will this little trick work in this situation. I am unable to get a constant or smooth idle on this engine.