1991 20HP Evinrude no acceleration

[saltchuckmatt]

Ok cylinder cutting out? It happens intermittently. I’ll be running and all of a sudden engine kicks up and starts doing this. Some also said over heating but it’s peeing fine. New pump

After re-reading, your motor runs fine and then goes into that mode correct? If that is true, it probably is electrical. Do you have a timing light?

 

[racerone]

It is very clear to me that it is suffering from ignition issues !

 

[saltchuckmatt]

Yea it is, that reminds me. When I was playing with the fuel pump where the line goes into it where the screen is I couldn’t get that to tighten up to the fuel pump. Wondering if the new o ring is too fat and won’t allow it to tighten up

If that isn't connected correctly or is stripped when you pump the primer ball has will spray out of that area. Easy to check.

 

[saltchuckmatt]

It is very clear to me that it is suffering from ignition issues !

I concur.

 

[67Mirro]

I concur.

I’m actually thinking it’s thermostat after seeing other videos doing the same thing, and that it’s hitting the slow mode so it doesn’t over heat

 

[jimmbo]

Pull the Plugs. 40 yrs ago we had a 25 behaving like that. After going thru all kinds of checks/tests, we plug the plugs. We found one of them with something, likely a bit of Carbon, bridging the Gap. Removed it, put the plugs back in, and all was good.

I doubt that engine has a "Slow Mode", there is no Computer controlling it.

 

[saltchuckmatt]

I’m actually thinking it’s thermostat after seeing other videos doing the same thing, and that it’s hitting the slow mode so it doesn’t over heat

No slow mode or safe mode on that motor. Shoot the top of the head with a infrared gun and see your reading. Check plugs like Jimmbo says but I think Racerone is correct. An electrical component is heating up and misfiring. Again, please confirm, motor runs fine and then goes into that mode, correct?

 

[67Mirro]

No slow mode or safe mode on that motor. Shoot the top of the head with a infrared gun and see your reading. Check plugs like Jimmbo says but I think Racerone is correct. An electrical component is heating up and misfiring. Again, please confirm, motor runs fine and then goes into that mode, correct?

It seems as though every time I putt out of the channel slow. I then go to power up once I get out and it does it every time. I think it’s over heating when it’s idling then when I go to power up after running for around 5-8 minutes at 4mph once I hit the main channel to power up it does this.

 

[racerone]

Magneto plate rotates.----May be a broken wire that you can not see.---May be a bare wire going to ground.------Do some testing or hurry to a repair shop !

 

[saltchuckmatt]

It seems as though every time I putt out of the channel slow. I then go to power up once I get out and it does it every time. I think it’s over heating when it’s idling then when I go to power up after running for around 5-8 minutes at 4mph once I hit the main channel to power up it does this.

I don't think it's overheating but you should check it. Sounds like it never runs fast good. You idle out and when you go to punch it on comes the problems. Could be an electrical component that only fails after heating up or like race says bad wire under the plate.

 

[jimmbo]

Attach a timing light and see if the Ignition is going South on either cylinder when it is acting up.

 

[67Mirro]

Will also mention I had it running with the issues it smelt hot so I took the hood off went to touch the water jacket cover could t even touch it with out being soo hot. That’s why I’m leaning towards not a ignition issue. Like so many say. I don’t think an ignition problem will cause overheating.

 

[saltchuckmatt]

Will also mention I had it running with the issues it smelt hot so I took the hood off went to touch the water jacket cover could t even touch it with out being soo hot. That’s why I’m leaning towards not a ignition issue. Like so many say. I don’t think an ignition problem will cause overheating.

Well in this long thread you talked about the engine running good but that the motor would jump into high rpm's and the boat would slow down (bad prop) then you quoted that you had a new pump never really saying it had heated up and then all this. Most motors when they heat up and you keep running them will just shut off or lock up. You better start from the top now and go through each procedure starting with compression check.