1976 25 hp Points question

[69 Alumacraft]

Motor runs great at idle and low speed but bogs when you try to open it up.So popped off flywheel, points and condensers are obviously new and in good shape, cleaned them up and regapped. Driver coil got biffed by the flywheel but seems to test out fine on my ohm meter which I am not sure I know how to use , I set it at 200 and get 1.1 resistance. Put everything back together and only getting spark on the top cylinder , switched "exterior coils" and get spark out of both on the top but neither on the bottom. Must be driver coil under flywheel correct? Other suspect is slight play in armiture plate but I have no idea how to tighten it. Have new driver coil on order any advice speculation appreciated.

 

[1946Zephyr]

Re: 1976 25 hp Points question

Both on the top and niether on the bottom? What does that mean?

 

[69 Alumacraft]

Re: 1976 25 hp Points question

If I switch the wires connecting the exterior coils the "top" or "number 1" wire will create a spark on either coil, the "bottom" or "number 2" wire will not create a spark on either coil. I left the coils in there original positions and just switch ed the connections to test them. Do I need to unbolt each coil and switch positions to test them?

 

[1946Zephyr]

Re: 1976 25 hp Points question

No, actually you don't. Switch wires should work just fine. So what you're saying is the number two wire coming from the driver coil is bad? That's the impression I'm getting. At least you know the exterior coils are both sparking.

 

[F_R]

Re: 1976 25 hp Points question

I hadn't thought of the wires between the points and exterior coils, but that is an excellent suggestion. If it isn't that, it just about has to be the points. Yeah, I know, new, and all that. New ones can be bad too.

On that motor, there is a time during the rotation when both sets of points are closed. Then one of them opens, firing it's related cylinder. What I'm saying is that when the one set opens, the other one must remain closed and making good contact.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

What about the play in the armature plate, how can I tighten it? Also, am I testing my driver coil correctly? I used and ohm meter and it reads about .8 resistance when I connect the two leads. It was mounted incorrectly by the last guy and the flywheel sheared off a very small piece of the metal on one side which deformed the metal so I filed it down slightly to make sure it stayed out of the way. Third question: If it is the wires that connect the coils what should I do , take them off, clean them up and reconnect? The points appear to make good contact and are not pitted or rusty at all.(F_R said "What I'm saying is that when the one set opens, the other one must remain closed and making good contact." This appears to be happening.

 

[1946Zephyr]

Re: 1976 25 hp Points question

Yes, try cleaning all your contacts and see if that corrects your problem.

 

[F_R]

Re: 1976 25 hp Points question

Sloppy armature plates were the norm when it was built. Just a poor design. Omc came out with a different plastic retaning ring which helped some. But they ran ok, in spite of the problem.

EDIT: Your driver coil test should be acceptable. Just the fact that it produces fire on one coil is a pretty good indicator that it is good.

I hate to keep harping on the subject, but if worse comes to worse, swap those points from side to side and see if the no-spark condition follows them.

Is the ground wire for the armature plate in place?

EDIT, EDIT: Really grasping at straws now...has this motor ever ran correctly for you? Could a previous owner have installed the wrong flywheel on it? The flywheel should have two sets of magnets, opposite each other. The "wrong" flywheel has only one set of magnets, possibly a non-magnetic balancer on the other side. Stranger things have happened.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

F_R :Motor ran great for 3/4 season and just died one day. Captain Zepher: If one external coil fires but not the other does that mean driver coil is good?

 

[OptsyEagle]

Re: 1976 25 hp Points question

The driver coil drives both cylinders so yes, if one cylinder fires then the driver coil is OK. Have you tried attaching a multimeter to the points and turning the cam until the points close and open to see what happens with the current?

It sounds to me that one set of points is not firing spark to the coil. If you disconnect the driver coil and the condenser and connect the points lead to a multimter with the other lead grounded, you should have a closed circuit that stays closed for most of the 360 degree revolution until the point opens and the circuit should open and then of course close again as the point closes. So in other words, you should only get one open circuit during each 360 degrees of revolution of the cam and the circuit should stay closed all the other time.

If you test both points this way and they operate well then it must be the wire going to your coil or perhaps the condenser. If one doesn't work exactly as I stated then it is the point causing your problem. Probably oil on the point surface or a bad point ground or something like that.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

replaced points and condenser on the bad side now getting spark on both cylinders!! Thanks guys, keep you posted when I run her.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

UPDATE: Not good, smokey and rough in tank, did notice one of the ignition coils is cracked but still produces a spark although neither consistently jumps 1/4 inch on tester. Next step is to pull flywheel again and see if points stayed at .020. Question: If coil produces any spark at all is it still good?

 

[F_R]

Re: 1976 25 hp Points question

Told ya it was the points. Now I'm telling you that it is supposed to be smokey in the tank. Not only that, but in addition to the "normal" smoke it is all loaded up with unburned fuel and oil from running on one cylinder. It needs to be "blown out" by running it at high speed awhile, on a boat. Put that sucker on a boat on the lake and dial in the carburetor. Then report back if it still is rough.

The cracked coil probably is good for now. But I'd suggest you replace it before it does break down.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

Will do, but... I pulled the plugs and the top cylinder the one with the good coil and spark was dry and the bottom was wet w/ fuel, this tells me the bottom is still not firing. Also, once the motor quick running well I did not run it much at all so I don't think all that much sludge built up. Third question I could not always get the spark to jump 1/4 inch on my tester more like 1/8 but this is a pull start and one has to be a contortionist to pull the engine over and look for spark at the same time. Does it really have to jump1/4 inch every time if you are pull starting or just rotating the flywheel by hand opposed to an electric start motor that will turn over quickly and consistently every time?

 

[kbait]

Re: 1976 25 hp Points question

I hook the wires to my spark tester and must have 1/4" bright blue spark by pulling recoil, or even a rope wrapped around flywheel. Not intermittent. If it can arc to ground from the cracked coil, it probably is.. a test run in the dark would definitely show if it's shorting to ground from that coil.

 

[OptsyEagle]

Re: 1976 25 hp Points question

Yes, the ignition needs to be able to jump a 1/4 inch gap in air. If the motor does not have enough voltage to do that it will struggle to spark the 0.030 inch gap in a compression environment.

You do need to pull hard on the starter rope to get this voltage. I believe you need at least 300 rpm to generate enough voltage to jump the gaps (1/4" in air, 0.030" in compression). Your problem you highlight is what wives and medium age children are for. They are useful for other things but definitely useful for holding up spark testers in darkened rooms. Friends will work as well.

The other test you can do is to fire the motor up in the barrel and with insulated plyers, pull one spark plug boot at a time. The motor should run OK on only one cylinder so if it quits on you when you pull a boot, you can assume the other cylinder was not firing or was very weak.

 

[F_R]

Re: 1976 25 hp Points question

There are other reasons a motor may run on only one cylinder. Rig up a spark gap on that lower plug wire and start the motor, and watch the spark as it runs (on the top one). WARNING--leave the plug in while you do this or you may start a fire. Also note if it sounds about the same as with both wires attached to the plugs. Or pull the plug wires one at a time as the previous post suggests.

BTW, it doesn't have to run very long to load up with unburnt gas if running on one.

My last comments on this one. Sounds like my credibility is in doubt.

 

[OptsyEagle]

Re: 1976 25 hp Points question

There are other reasons a motor may run on only one cylinder. Rig up a spark gap on that lower plug wire and start the motor, and watch the spark as it runs (on the top one). WARNING--leave the plug in while you do this or you may start a fire. Also note if it sounds about the same as with both wires attached to the plugs.

You might as well run that test and after run my test where you take the running motor and pull off one spark plug boot at a time (remember to use insulated plyers) to see what happens.

If you take the flywheel off again, you also might want to run F_R's test and my test as well. Not sure if you did this. F_Rs test was to check that one set of points was not sparking and then to switch them to see if the problem moved with the point or stayed with the wires.

My test was to disconnect the condenser and the driver coil and connect a multimeter (continuity tester) to the points lead and the other multimeter lead to the ground on the powerhead. Now if the point is closed the multimeter should indicate circuit continuity. Now slowly rotate the points cam as slow as you can. At some point the point will open and the continuity will stop. Then the point will close and indicate circuit continuity again. What you want to verify is that the point only opens once and stays closed through the entire remainder of the 360 degree revolution. This test is really testing the integrety of each point and should be done on both points.

 

[69 Alumacraft]

Re: 1976 25 hp Points question

F_R I do not question your advice, and appreciated any help . Pulled flywheel and checked points again. So, .020 will fit snug and .022 will not go through unless I push it which makes the point pivot and allow it to pass through. Is this the correct method? Ran her in a barrel and pulled the lower plug wire off (the one with the cracked coil) and it made no difference, the motor kept running. So I need a coil, right?

 

[F_R]

Re: 1976 25 hp Points question

Well, a cracked coil always is suspect and should be replaced anyway. But I can't guarantee that will fix the problem. As I said, there are other reasons for running on one cylinder.