I’m having a problem with the motor missing. It is more noticeable when cold and is enough to stall the motor at times. At idle the motor increases revs then misses, slows down and starts the cycle over again. It seems to run ok at speed.
What I’ve tried so far.
Link and sync.
Cleaned carb several times, even removed welsh plug to check.
Plugs.
Comp 140, 140, 140
New fuel filters and lines but have not changed primer bulb.
Switched from main fuel tank to portable tank.
Rebuilt fuel pump.
Looked at reeds that I could see. Motor only has 1 carb so can only see 1 ? reed blocks.
Checked fuel enrichment solenoid is working ok.
On the electrical side of things I’m a bit out of my depth when it comes to testing Ignition components but this is what I have checked.
Stator 685 ohms on ignition, between green/white and white/green. On charging circuit 0.5 ohms, between yellow wires. ( the manual I have says this should be 0.24 – 0.25) I don’t have a DVA meter to do other tests and also not sure how to do the tests.
Partial tested CDMs.
A to C terminals 1240 ohms on all.
High tension leads to A 1240 ohms on all.
Earth wires had a good ground.
The stop wire (black /yellow) was open when ignition switch is on and closed when key is switched off.
I’d like to check the ignition more thoroughly but would like some help please.
My other thought is I’m getting water into the motor causing it to run rough when it is cold at idle. I’d like to chase other possible causes first as the motor has been run is salt water for the last 4 years. The original paint is still on all the bolts so they have not been removed from new.
Photo of the plugs. # 1 cylinder on the left, # 3 on the right. 6 hours running from new.
The plugs have always graded lighter from the top to darker on the bottom. I’m told this is due to having a single carb feeding 3 cylinders. They have done this ever since I have owned the boat and before the misfire problem.
I’ve had the motor running without the miss a couple of times. This usually happen after I’ve had the cover off the motor after working on it. The boat is stored under a large tarp and condensation can build up. I keep thinking I have found the problem but it keeps coming back later.
It’s not exhaust fumes as the miss occurs with the cowl off.
I’m at the point of getting a outboard mechanic to diagnose the problem. They have the tools and knowledge. I don’t want to be throwing parts at the motor in an attempt to fix it.
What should I be looking at next?
Thanks
Dean
Recent plugs
Plugs 2 years ago
What I’ve tried so far.
Link and sync.
Cleaned carb several times, even removed welsh plug to check.
Plugs.
Comp 140, 140, 140
New fuel filters and lines but have not changed primer bulb.
Switched from main fuel tank to portable tank.
Rebuilt fuel pump.
Looked at reeds that I could see. Motor only has 1 carb so can only see 1 ? reed blocks.
Checked fuel enrichment solenoid is working ok.
On the electrical side of things I’m a bit out of my depth when it comes to testing Ignition components but this is what I have checked.
Stator 685 ohms on ignition, between green/white and white/green. On charging circuit 0.5 ohms, between yellow wires. ( the manual I have says this should be 0.24 – 0.25) I don’t have a DVA meter to do other tests and also not sure how to do the tests.
Partial tested CDMs.
A to C terminals 1240 ohms on all.
High tension leads to A 1240 ohms on all.
Earth wires had a good ground.
The stop wire (black /yellow) was open when ignition switch is on and closed when key is switched off.
I’d like to check the ignition more thoroughly but would like some help please.
My other thought is I’m getting water into the motor causing it to run rough when it is cold at idle. I’d like to chase other possible causes first as the motor has been run is salt water for the last 4 years. The original paint is still on all the bolts so they have not been removed from new.
Photo of the plugs. # 1 cylinder on the left, # 3 on the right. 6 hours running from new.
The plugs have always graded lighter from the top to darker on the bottom. I’m told this is due to having a single carb feeding 3 cylinders. They have done this ever since I have owned the boat and before the misfire problem.
I’ve had the motor running without the miss a couple of times. This usually happen after I’ve had the cover off the motor after working on it. The boat is stored under a large tarp and condensation can build up. I keep thinking I have found the problem but it keeps coming back later.
It’s not exhaust fumes as the miss occurs with the cowl off.
I’m at the point of getting a outboard mechanic to diagnose the problem. They have the tools and knowledge. I don’t want to be throwing parts at the motor in an attempt to fix it.
What should I be looking at next?
Thanks
Dean
Recent plugs
Plugs 2 years ago
