Pulled spark plug wires

[jlh42581]

Re: Pulled spark plug wires

In my case with my fuel pump I was missing one check valve. I could run fine to 2500rpm then just bog out and die, crank right back up.

 

[brian3127]

Re: Pulled spark plug wires

Alright i didn't have much time to work on the cylinders plug wires because I was trying to get the tach wired up. But what I was able to do was pull the wires.
I pulled the top wire and the motor ran like nothing happened.
Then I pulled the bottom on and the motor still ran but real rough. Hope that helps you maybe figure out what might be happening. The top cylinder has between 120 and 125 lbs of compression and the bottom has between 115 and 120 lbs

 

[nwcove]

Re: Pulled spark plug wires

yer chasing your tail , compression is good. as mentioned a few times in this thread, you need to swap coils from top to bottom and see if the issue follows.

 

[OptsyEagle]

Re: Pulled spark plug wires

Alright i didn't have much time to work on the cylinders plug wires because I was trying to get the tach wired up. But what I was able to do was pull the wires.
I pulled the top wire and the motor ran like nothing happened.
Then I pulled the bottom on and the motor still ran but real rough. Hope that helps you maybe figure out what might be happening. The top cylinder has between 120 and 125 lbs of compression and the bottom has between 115 and 120 lbs

Is this with the spark plug boots and clips on normal or reversed?

 

[brian3127]

Re: Pulled spark plug wires

Is this with the spark plug boots and clips on normal or reversed?

Normal. The spark plug wire for the top cylinder isn't long enough to reach the bottom cylinder but the bottom one is long enough to go to the top. So when I switch the coils I'm going to have to take the coils off the motor and switch their places.

 

[Boss Hawg]

Re: Pulled spark plug wires

Normal. The spark plug wire for the top cylinder isn't long enough to reach the bottom cylinder but the bottom one is long enough to go to the top. So when I switch the coils I'm going to have to take the coils off the motor and switch their places.

Thats what you need to do anyway-

 

[brian3127]

Re: Pulled spark plug wires

Here are my findings warmed the motor up then pulled spark plug #1 the motor spit and sputtered. Then I pulled 2 it ran like nothing happened. Then I reversed the coils and did the same to both cylinders. It stayed the same. Spit and sputtered on 1 and ran like nothing happened on 2.
Another thing I noticed is when it was warming up the bulb on the gas line was soft so I pumped it and it never stayed hard I could squeeze it maybe a quarter inch on each side or more

 

[OptsyEagle]

Re: Pulled spark plug wires

Is the motor still stalling on you? It looks like any problem that you may have is a problem with the bottom cylinder. We have eliminated the coils and coil wires. Your compression seems good and you said that you reset the points on the motor. What did you do to clean the points? Are you sure they are both set well at the 0.020"? Did you do an external spark test, afterwards, to see if they can jump a 3/8" gap? When was the last time you changed and gapped the spark plugs and what plugs are you using?

What operational problems are you having right now? I usually say that if one cylinder can keep the motor running then that cylinder is doing pretty good, even if it is a little rough. I mean it would take a lot of work from one cylinder to overcome the compression of two cylinders and keep running. I am sure your crankcase seals are degraded after all these years and the bottom one would most likely require a powerhead removal to replace, so depending on the operational problems. If I felt my bottom was running with 80% efficiency instead of 100%, I doubt I would bother with that fix, etc.

 

[brian3127]

Re: Pulled spark plug wires

I put new points set at .02 and new condenser the spark jumps about a half inch gap and now I'm putting on new spark plugs ngk b7hs set to .03 gap it seems to be running a lot better

 

[OptsyEagle]

Re: Pulled spark plug wires

Take her out on the water and let us know if you have any problems (maybe don't go too far at first). I suspect that previously, you probably had a dirty point. As I said, optimally both cylinders would run that thing alone flawlessly, but after 38 years you have to give it a little slack. As I said, a little loss of crankcase seal and that type of thing, will sometimes make one cylinder work better then the other. With older motors like yours, I usually say that if one cylinder keeps the motor running, in any fashion, that cylinder has passed the test.

 

[brian3127]

Re: Pulled spark plug wires

Just got back from a cruise on the lake it ran pretty good. After we got past the no wake zone i punched it and it took off. It ran good for a bit. Then at wot it felt like it was loosing power so I backed off and it straightened out. Could that because the bulb on the fuel line goes soft. What is the Rpm supposed to be at when wot.

 

[OptsyEagle]

Re: Pulled spark plug wires

The bulb does not stay hard when the motor is running. Could you go back to WOT after it straightened out. Perhaps you have an intermittent problem.

This brochure says that at WOT you should get between 4000 to 5000 RPM.

http://www.old-omc.de/j_1975/seite01.jpg

 

[brian3127]

Re: Pulled spark plug wires

When we were out at full throttle you could feel the boat miss alittle so I backed it off then went back to wot and same thing. I never checked the build when we were at wot but when we got back I checked it and it was soft. Wot I'm at 4000

 

[OptsyEagle]

Re: Pulled spark plug wires

The RPMs seem to be in spec but on the low side. The other thing I would be interested in is if the carb is synchronized with the timing plate. Unfortuneately I am not familiar with your motor enough to advise on how to do this and/or make adjustments. As you know, the timing of your spark is initially set by the point gaps, however that timing needs to be advanced as the RPMs increase and retarded as they decrease. This is done by synchronizing the carb to the timing plate.

On my motors (5.5Hp to 15Hp) there is a plate that rotates when the throttle is increased/decreased that pushes on a roller that is connected to my carb's throttle butterfly. On that plate there is a mark and the idea is that the mark should be in the center of the carb's roller when the roller "just" touches the cam. This ensures that my spark timing is adjusted to the right timing as my RPMs increase or decrease. Since your motor seems to be doing its complaining at WOT, perhaps this synchronization is off.

If you have a manual you could look up the procedure. I would imagine it would be in the carburetor section. If not perhaps someone that is familiar with your model would know how to adjust it... or perhaps you have already done this.

 

[brian3127]

Re: Pulled spark plug wires

I bought a book and did that 2 days ago

 

[brian3127]

Re: Pulled spark plug wires

Now I have another problem my wot is about 2000 so lost about 1000 rpm

 

[OptsyEagle]

Re: Pulled spark plug wires

Sounds like you are dropping a cylinder again. This would be a great time to do another spark test to see if both are firing.

 

[brian3127]

Re: Pulled spark plug wires



The plug on the right came from the top cylinder
The one on the left was wet.

 

[fishfeatures]

Re: Pulled spark plug wires

plug is looking a bit too clean... I reckon you're getting water in that cylinder, that's why it's not running right and only on one cylinder. Remove the head and check the head gasket for wear is my advice..... rem to torque the bolts back correctly when re installing.

 

[brian3127]

Re: Pulled spark plug wires

Is it a big job to change the head gasket