No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

[blk98gt]

My previous thread talked about no power. Turned out to be no spark on one side of the motor in cylinders 2 and 4. Where should I go now?

 

[F_R]

Re: No spark in 2 of 4 cylinders. 1961 75hp

Re: No spark in 2 of 4 cylinders. 1961 75hp

My previous thread talked about no power. Turned out to be no spark on one side of the motor in cylinders 2 and 4. Where should I go now?

It has two sets of breaker points, each set fires two cylinders. So obviously there is a problem with one set. Clean them up shiny bright and adjust gap to .020". Or just replace them. Iboats has 'em.

 

[blk98gt]

Re: No spark in 2 of 4 cylinders. 1961 75hp

Re: No spark in 2 of 4 cylinders. 1961 75hp

We cleaned the breaker points.
All hail F R. But still a bit of a problem. Below is a video of the idle (on all 4 cylinders with some sea foam). At 38 seconds notice a misfire? It does that once a minute at idle and little more under throttle. You think it's still caused by the breaker points?
BTW Compression seems low. We checked it when the motor was cold (50 degrees). 80-78-79-72

http://www.youtube.com/watch?v=vVU4sTH1fhc

 

[lindy46]

Re: No spark in 2 of 4 cylinders. 1961 75hp

Re: No spark in 2 of 4 cylinders. 1961 75hp

We cleaned the breaker points.
All hail F R. But still a bit of a problem. Below is a video of the idle (on all 4 cylinders with some sea foam). At 38 seconds notice a misfire? You think it's still caused by the breaker points?
BTW Compression seems low. We checked it when the motor was cold (50 degrees). 80-78-79-72

http://www.youtube.com/watch?v=vVU4sTH1fhc

Did you do a decarb with Seafoam? Or just put some Seafoam in the gas? May want to try putting seafoam in the cylinders - get them pointing up - and let it soak at least overnight. Compression will probably improve some. At least all 4 are fairly close. Seems to idle pretty good, except for that miss.

 

[blk98gt]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

We did decarb with sea foam on the water for what it was worth since it was only running on two cylinders a week ago. In the video it was sea foam in the gas only from last time.

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

You sure the gauge is accurate, those numbers seem weird for a 4 banger across all cylinders. That isn't a misfire, that sounds like a complete loss of power then it came back, a misfire is way shorter than what that motor did.
BTW where is my all hail pic, I told you it was only firing on 2

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

Now onto troubleshooting. You had the flywheel off, any frayed wires, how did the coils look? You may want to replace the points and condensers instead of just cleaning them, you can't clean condensers. What was the condition of the plugs after you had it running, are they the right plugs for the motor? Motor feel cool at idle?

 

[blk98gt]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

All hail

Now down to business.
The gauge was brand new although I thought you are supposed to check compression on a warm motor but we checked it cold.
Spark plugs do not seem right as they are j6c instead of j4c (or are they the same) but I didn't think that would be the problem. I will get the correct plugs.
Both banks after a long idle were in the upper 130 degrees on the heads.
I called it a miss fire but really not sure if that's what that is. Maybe a miss fire on the entire bank of cylinders 2 and 4 that were initially not firing?
This motor I believe has one coil and everything else looks new. Except the one breaker point that we cleaned.

Should I take the next step to replace the old breaker point and spark plugs?

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

HAHAHA That rocks. I was totally joking but that is good stuff.

Compression is a little low but it's not 80, 20,40,5, the numbers are all within 10%. As far as temp, I yanked my 15 out of the garage at 10C and tested it dead cold at 95 psi in both cylinders. I don't like that 72, seafoam may help bring it back up.

One coil??? I don't know your motor but I know twins of that vintage have 2 coils, does this thing have a distributor?

Points condensers and plugs wouldn't hurt.

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

Just googled, it's got a car coil and a battery so does it have a disti??? I'm thinking maybe or are they fed from the timer?

 

[blk98gt]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

It does have a distributor, a car like coil but the battery is not needed to run the motor. Just powers the starter. Just ordered the breaker point kit. The condenser looks new along with the other breaker point and the wiring under the pulley so I think someone may have been working on this motor before putting it in the garage.
Honestly I don't even know what the condenser does.

Back to the compression, maybe the compression is low because I was using a car jump starter which does not crank the motor very well on it's own. Just like compression is lower by using the pull cord.

 

[lindy46]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

It does have a distributor, a car like coil but the battery is not needed to run the motor. Just powers the starter. Just ordered the breaker point kit. The condenser looks new along with the other breaker point and the wiring under the pulley so I think someone may have been working on this motor before putting it in the garage.
Honestly I don't even know what the condenser does.

Back to the compression, maybe the compression is low because I was using a car jump starter which does not crank the motor very well on it's own. Just like compression is lower by using the pull cord.

If you can crank it for 2 or 3 seconds on the jumpers, you should get a pretty good compression reading.

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

It does have a distributor, a car like coil but the battery is not needed to run the motor. Just powers the starter. Just ordered the breaker point kit. The condenser looks new along with the other breaker point and the wiring under the pulley so I think someone may have been working on this motor before putting it in the garage.
Honestly I don't even know what the condenser does.

Back to the compression, maybe the compression is low because I was using a car jump starter which does not crank the motor very well on it's own. Just like compression is lower by using the pull cord.

I don't think the speed at which a motor rotates would have any effect on compression, the air goes into the gauge regardless. Pull the cap off and have a look inside the cap at the contacts and the condition of the rotor, clean off carbon build up. If it will run without the battery disconnected then it is a magneto system, point and condenser should indicate this.

The condenser is a CAPACITOR in effect and stores the electrical charge generated by the magneto until the points close to initiate the spark for the plug.

 

[cougar1985]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

I don't think the speed at which a motor rotates would have any effect on compression, the air goes into the gauge regardless. Pull the cap off and have a look inside the cap at the contacts and the condition of the rotor, clean off carbon build up. If it will run without the battery disconnected then it is a magneto system, point and condenser should indicate this.

The condenser is a CAPACITOR in effect and stores the electrical charge generated by the magneto until the points close to initiate the spark for the plug.

actually that motor will not run without the battery as FR told me in my post and confirmed by the manual,the battery is a intergril part of the system.if the coil is in the distributor it is a mag system,if the coil is mounted between the cylinders low down it is a battery distributor system and needs a good battery.

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

actually that motor will not run without the battery as FR told me in my post and confirmed by the manual,the battery is a intergril part of the system.if the coil is in the distributor it is a mag system,if the coil is mounted between the cylinders low down it is a battery distributor system and needs a good battery.

I figured, went back to your post and it said your's was a 63, his is a 61, must be some sort of a hybrid system, car coils and caps with magneto's.

 

[cougar1985]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

I figured, went back to your post and it said your's was a 63, his is a 61, must be some sort of a hybrid system, car coils and caps with magneto's.

had a hard time seeing where his coil was ,on mine its mounted low down at the back between the cylinders at the edge of the cowling base before the water splitter? then 2 wires come from the neg side of the coil with 1 going to the dist and the points(black).with no battery mine does squat!

 

[cougar1985]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

It does have a distributor, a car like coil but the battery is not needed to run the motor. Just powers the starter. Just ordered the breaker point kit. The condenser looks new along with the other breaker point and the wiring under the pulley so I think someone may have been working on this motor before putting it in the garage.
Honestly I don't even know what the condenser does.

Back to the compression, maybe the compression is low because I was using a car jump starter which does not crank the motor very well on it's own. Just like compression is lower by using the pull cord.

if yours runs without a battery then its a mag system,is the coil mounted in the dist?heres a couple of pics of mine which is a battery ignition system with points etc.

heres the coil, next is the dist.

apparently both types of systems were used up till 1965.i did the same when i was checking compression and when i used a good battery i went from 60 to over 90!

 

[bktheking]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

man that's old tech, it must work though

 

[lindy46]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

If the coil is outside the distributor, then it is most likely a battery-distributor system with an alternator. It would need a good battery for the engine to run.

 

[cougar1985]

Re: No spark in 2 of 4 cylinders. 1961 75hp (new idle video)

just one thing to think about,if the coil has been replaced and the previous owner went the auto coil route that might be your problem.with few exceptions a auto coil has a built in resistor where as the orginal coil for your motor had a resistor wire!if you have a auto coil and dont disconnect the resistor wire your getting too much resistance and can have problems.also make sure the previous owner put in the correct rotor!the mag system rotor and the dist/battery rotor will both fit but are differnt.if you have the wrong rotor on there your motor will never run right!just a couple of things to look for .good luck!