1986 140 hp Evenrude

[wal1809]

We are building a house on Matagorda Island. Rebuilt a pontoon boat to ferry all of the supplies. The engine was in dire need of some work.

Ordered a new fuel pump as previous owner had an electric pump on it. The vro was already gone.
The problem is it runs fine at slow speed. The secondary jets kick in every now and again but only for a second or two and then off again.

Took the carbs off a little while ago and it is 100 percent obvious they have recently been gone through. Super clean. I checked every single hole and tube on all 4 carbs. Unless the gaskets had a leak, dirty carbs are not the problem.

Plugs are new. They seem wet today but not out of ordinary. I have not checked the arc distance. Not really sure how to do that.

This problem of the motor trying to die started when we left calm water and hit the wakes at the jetties. It was obvious to both of us, the missing out started when we hit waves. The secondary jets will kick on then off but mostly off.

I am starting to lean to this being a fire problem rather than fuel. Educate me fellas, please.

 

[racerone]

Fuel problems are gradual in nature.----Ignition missing is more an instant change in engine power / RPM.

 

[Captain Greg]

check the wires coming from the stator for any type of short also timing base

 

[wal1809]

I feel this is electrical. Some time back headed to the island. His sone waves, exact same missing out and eventually died, towed in. Found the problem immediately. I could see the red wire headed to the power pack was not properly secured. It made contact with the underside of the flywheel, ate the wire's protective coating, shorted and died. I just coated and secured the wire.

Today. While looking for anything out of ordinary I took off the power pack and noticed black tape on the same red wire from the earlier problem. I took the tape off and found a problem. The red wire in the harness had previously broken off at the harness plug. The previous owner bypassed the ug with a red jump wire. Thats the wire that wasn't secured and made contact with the flywheel.

I just ordered a new power pack and going to replace the jump wire and figure out how to fix the harness plug wire. I am not a fan of twisting wires together and black taping them. I am a solder the joint, liquid tape the open area and sealing it all with heat shrink tubing.

Will let yall know what else I find.

 

[wal1809]

Fuel problems are gradual in nature.----Ignition missing is more an instant change in engine power / RPM.

I would have to tend to agree with your statement here.

 

[wal1809]

check the wires coming from the stator for any type of short also timing base

Updating. I pulled the carbs to find they have recently been rebuilt, super clean, not even discolored.

I agree with electrical can be the issue. I have already replaced the power pack. I suspect the stator could be the issue.

When I run the boat it plows through the water with the efficiency of a pig. Every now and again it surges forward and getthe response I would expect from wide open throttle. Then it shuts back to pig status.

I suspected plugged carbs but not anymore. A 300 dollar part is not something to just try though. Like to chat about maybe the stator not supplying the voltage needed at full throttle.

Lets hear what you got. BTW, bad arse forum, thank you for having me.

 

[wal1809]

BTW. This is the boat we are talking about. Life is strange, as I have more invested in the lumber than the boat. The boat a trailer were free. The motor was free. The console and leaning post were 100 bucks.

 

[racerone]

I can not see , hear or feel your motor.----Post your compression values.-----And does spark jump a gap of 3/8" or more on all leads ?

 

[wal1809]

I can not see , hear or feel your motor.----Post your compression values.-----And does spark jump a gap of 3/8" or more on all leads ?

I have never done a spark test measuring distance. Do you open the plugs to 3/8s or is there a tool I can pick up?

 

[wal1809]

I read on a tractor forum they buy a new spark plug, cut that bent metal thing off and just hold it 3/8s from a ground source and bump it over. Yall do this?

 

[racerone]

Glue 2 pieces of wire on a piece of carboard.-----3/8" gap between them.----Then one end in the plug boot.----Other end clipped to the block.

 

[wal1809]

I can not see , hear or feel your motor.----Post your compression values.-----And does spark jump a gap of 3/8" or more on all leads ?

Compression is all within 10lbs
The top 2 cylinders will fire over a half inch. No fire on the bottom 2 cylinders.

 

[racerone]

Running on 2 cylinder would be the reason for low power output.

 

[wal1809]

Running on 2 cylinder would be the reason for low power output.

I would tend to agree. Why intermittent power? You reckon the coils are working then shutting off intermittently?

 

[ct1762@gmail.com]

you need the factory manual, dva adaptor and a multmeter to read cranking voltage values for the pack, charge coil and timer base. that way you can stop guessing. you can swap coils in the meantime... see if the issue follows them.