1974 Evinrude 135 dies at low speed.

[Islandlaker]

I have a 74 or 75 135 Strangler. Motor runs great at most speeds, at the lowest speed like when I am trolling the motor tends to die at random times. The motor then will only start if I turn the fast idle lever all the way up. I am thinking of swapping out the entire fuel pump assembly or just the fuel filter itself. Any suggestions on this?

 

[interalian]

What's your idle speed? And when were the carbs last cleaned? Compression?

 

[Islandlaker]

Bought the motor this year so I do not know when the carbs were cleaned last. Same with the compression, I have never tested compression before. The slowest speed the motor with go when I put it into forward is about 2.5 mph, that is when the motor dies. Usually about once every twenty minutes. When I run it any faster then the slowest setting there is never a problem.

 

[emdsapmgr]

May be a fuel restriction inside the carbs. Agree, you may want to clean them first, which will include removal of the jets and a close visual inspection for any debris. Compression is everything to a 2- stroke, so verifying that the compression is strong is a must-provides a solid basis for any investment you make in repairs.

 

[interalian]

It might just be idling too low. Do you have a tachometer? About 700 rpm in gear while tied to the dock is the right setting. Much less and the odd misfire at idle will blow out the candle.

 

[Islandlaker]

Sounds like some simple advice, thanks! I was all ready to swap out the fuel filter and probably the assembly but I will try and mess around with the idle speed first. I do not have a tachometer on the motor. I would imagine like an atv or motorcycle there is a idle screw on the motor. I could play around with it and turn it up a quarter turn or so. Doing some searching on the forum I found a couple other easy solutions I could try like the chevron fuel system cleaner and the decarb treatment.

 

[jimmbo]

Bought the motor this year so I do not know when the carbs were cleaned last. Same with the compression, I have never tested compression before. The slowest speed the motor with go when I put it into forward is about 2.5 mph, that is when the motor dies. Usually about once every twenty minutes. When I run it any faster then the slowest setting there is never a problem.

Two stroke engines generally don't run at the lowest speed very well for long periods of time. They tend to load up and stall. 20 minutes of slowest idle before a hiccup is pretty good in my books. If you try adjusting the idle speed, stay away from the carbs. Idle speed on these engines is controlled by how far the timing is retarded from TDC. There will be a screw that goes against a stop to limit the amount of retard.

 

[Islandlaker]

Jimmbo, thanks for the warning. Is there a way to adjust the idle speed away from the carbs then? I am ordering a manual today, I think I need one!

 

[Islandlaker]

On a side note anyone know the recommended spark plug for these motors are? I can't seem to find that information anywhere.

 

[emdsapmgr]

You can find out a lot of useful information at the factory exploded parts diagram website, including the correct plugs. Check it out: epc.brp.com

 

[interalian]

Your idle adjusts with a large slotted screw a couple inches above the throttle arm pivot. There is a plastic cap on the threaded end that bears against the block. Similar to this: