1988 Evinrude 25 with backfire

[mike_kern]

I have a 1988 Evinrude 25 (E25RLCCA) that has a case of the hiccups. I just got this engine out and going after sitting for several years. It was put away because of a cracked carb and that is now replace and at the same time I did an impeller, gear case seals, and thermostat. Then engine starts and runs, but seems to have the hiccups. It will run fine for a few turns over then have a backfire, but it will keep running. If I unhook either of the coils and let it run on just 1 cylinder it will idle along and even rev up fine. Any input on what this could be would be great! Thanks in advance!

 

[Bondo]

Re: 1988 Evinrude 25 with backfire

I have a 1988 Evinrude 25 (E25RLCCA) that has a case of the hiccups. I just got this engine out and going after sitting for several years. It was put away because of a cracked carb and that is now replace and at the same time I did an impeller, gear case seals, and thermostat. Then engine starts and runs, but seems to have the hiccups. It will run fine for a few turns over then have a backfire, but it will keep running. If I unhook either of the coils and let it run on just 1 cylinder it will idle along and even rev up fine. Any input on what this could be would be great! Thanks in advance!

Ayuh,.... Welcome Aboard,.... Sounds like it's starvin' for fuel,...

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

Ayuh,.... Welcome Aboard,.... Sounds like it's starvin' for fuel,...

Both plugs look like its running a bit rich if anything...

 

[boobie]

Re: 1988 Evinrude 25 with backfire

Sounds more like it's running lean.

 

[jbjennings]

Re: 1988 Evinrude 25 with backfire

Is it a backfire or a lean "sneeze"? Is the carburetor perfectly clean? If a true backfire then about the only thing it could be is incorrect timing. Possibly a sheared woodruff key that's let the flywheel spin slightly on the crankshaft. If a lean sneeze then there is an air leak or the idle circuit is clogged in the carb.
JMO,
JBJ

 

[racerone]

Re: 1988 Evinrude 25 with backfire

Sounds like it is running lean on low speed mixture or throttle is opening too soon !

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

I am wondering if it is more along the lines of electrical. The carb is clean, both the main and the low speed/idle circuit are clean, all new fuel lines, new tank, and new fuel. I had the carb off again last night just to verify. After running the engine again (backed into the lake NOT using a fake a lake) is still had its backfire/sneeze. I pulled out the plugs and they both are just a few shades darker than paper bag brown. Do these engines ever fall out of time? I have never timed one of these and this could possibly be the issue.. Thanks again for all the advice!

 

[racerone]

Re: 1988 Evinrude 25 with backfire

The sneeze is classic of a carburetor that is too lean on the low speed mixture or the throttle is opening too soon.-------Timing ?----the ignition timing is fixed at the factory and rarely needs adjusting for the life of the motor.------Use a timing light and observe the flash if you insist on it being an electrical issue.

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

When you say the throttle is opening too soon what exactly do you mean? Tonight when I get home I will try opening up the idle circuit a ways farther and see what that does for me. I will also hit it with the timing light and see what it looks like.

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

After opening up the carb and giving it yet another good cleaning I am still in the same boat. the carb is spotless and the idle circuit can breath easily. Now it will run perfect for several minutes then start missing for a minute then it cleans up and runs just fine. Any other thoughts on what it could be??

 

[racerone]

Re: 1988 Evinrude 25 with backfire

Is there a thermostat installed in the motor ?----------Can you post a picture of the adjusting collar on the small diameter rod that goes from the back to the carburetor.---Post a picture of it with the throttle at slowest idle.---There should be a space at that collar at idle.

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

I just put a new thermostat in when I was doing the other work on the engine. On this carb there is not adjustment rod. there is just the one throttle link that runs from the throttle shaft. I can still take a few pics of it tonight when I get home.

 

[racerone]

Re: 1988 Evinrude 25 with backfire

Sorry, but you need to look at your motor again !!!----There is a rod about 8" long that goes to the back of the motor.--------It has an adjustable collar on it.----That collar is often adjusted by folks.-----It looks wrong to the untrained eye when in fact it is correct.-----Possibly opens the throttle too soon on your motor !!

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

Ok, I will take a look at it tonight. Is that something that can get out of adjustment just over time? How should it be set? Since my dad bought this engine new in 88', it has had little more done than basic maintenance to it. I would be willing to guess that nobody has ever adjusted the rod. Thanks again!

 

[racerone]

Re: 1988 Evinrude 25 with backfire

Sorry, from say 1000 miles away I can not tell what has been done / has not been done on this motor.

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

I was just wondering if there was a setting like on a needle or something in a carb. I will play with it tonight and see what I can figure out. im gonna owe ya a case of beer! :thumb:

 

[mike_kern]

Re: 1988 Evinrude 25 with backfire

That rod was the issue. That rod is what adjusts the timing advance, and it was way off. after playing with it some using the timing light she runs great just sitting on the trailer in the lake! This weekend I will actually unload it and see what she does! thanks for all the help!!!!