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1987 evinrude 60hp low idle exhaust backfire.

O

Omcking

Member
Hello all,
as the title states I’m having an issue with my 1987 evinrude 60 hp. Or several. So to start I’ll list what has been done currently. New parts include starter, fuel pump, spark plugs, carbs rebuilt, power pack, rectifier, fuel tank, fuel hose with new primer bulb, all new fuel lines on the engine and I believe that’s it. So when I fire the engine up it will not idle. If I give it some throttle and up the rpms to about 1200 or better then I can get it to idle but it has a nasty backfire through the exhaust. The #1 cylinder spark plug once pulled looks perfect nice and tan. The #2 and#3 cylinder spark plugs once pulled are not good. The #2 spark plug comes out black and wet and the #3 plug comes out black and dry. There is no air fuel mixture that I know of on the individual carbs. Can someone please help me out. I believe it may be timing related but I can’t set the timing without it being able to idle at the proper rpm. If someone can shoot me in the right direction that would be great.

thank you.
 
I have also checked and made sure I wasn’t sucking air in someone around the halves where they come together or around the carb. So whatever the issue is it seems to be on the number 2 and 3 cylinders.
 
Start with posting the compression numbers.-----Are you running it on a hose ?------Orange / stripe wires going to the correct coil ?----Orange / green on the bottom ?----Sure is a lot of $ spent on all the parts !!!
 
Trust me Im sick of spending money on this thing. Compression is 118 #1 cylinder and 115 on the other 2. And yes I believe I have the correct wires going to the correct cylinders on the coils.
 
Model # of the motor ?----Checked the flywheel key ?-----Any evidence of water on the plugs ?------If this is a 49 cubic inch motor then compression is low.------The 49 cube motors alse suffered from warped exhaust manifold plates.-----Are all carburetor throttle plates CLOSED at idle ?----I think this should be easy to figure out but I can not see , hear or feel your motor.
 
Model number is e60tlcuc have not checked the flywheel key. No evidence of water on the plugs. Gas yes. Throttle plates seem to close at the same time I believe the engine will run properly because I can idle it up and it’ll scream at full throttle. I understand man I feel like it should be stupid simple I just can’t put my finger on it.
 
My tester would read 140 on one of those.------So bring your motor over.------I can fix it without having to order any parts.----Also DO NOT rev it up to full throttle on a hose.----In gear the motor really is still in neutral as the prop does no work.
 
You say bring it over I totally would lol. I’m sick of working on it and believe I’ve done everything I know how to do. I just wanna go fishing
 
You stated that you have a hard time believing that your compression is " low "-----Trouble shooting can be challenging if you are working on one of these wonderful motors for the first time.-----Fact----Your motor should be an easy fix in my opinion.
 
I totally agree with you it should be something simple I just can’t figure it out. When I start the engine I can’t get it to idle at anything less than 1200 rpm and that’s with a nasty backfire. It is my first time working with one of these engines so I’m kinda lost at this point. I would think it would be air fuel mixture adjustment on the 2 and 3 cylinder carbs but there is no adjustment for the 2 and 3 cylinder.
 
Are you saying it only backfires at 1200 or1200and above? The motor does not have to run for a timing lite to work it only has to produce spark.
 
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It will only backfire at 1200 if I try to idle it lower it continues to backfire and eventually dies. If I rev it up past 1200 it runs like a champ. It seems that the bottom cylinder is getting to much fuel as it almost always fouls which I believe is causing the backfire
 
I’ve never had the motor actually running correct. I bought the boat as a project and getting the engine running perfect is the last thing on the list. So I’ve never actually had it on the water.
 
Okay. So I believe I have located the problem. My third cylinder is running extremely rich. So I took and blocked the fuel line going to the third cylinder and it runs like a dream on 2 cylinders. The 3rd carbueratorn has been rebuilt and is in perfect working condition. Which leaves me to believe the reed valve in the third cylinder is messed up.
 
Lol really don’t want. Pretty dumb what it ended up being. The orange wires coming off the power pack were wrong and I had just overlooked it.
 
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