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Pulling my hair out!!

393Clevor

393Clevor

Regular Contributor
Long story.... lol
Ok from the start, bought this 1956 QD-17 10hp and from the get go it ran like poop, backfiring, misfiring, stalling.. got bad enough it sheared the key way on the flywheel..

I replaced coils, points, condensers, new solid core wires and spark plugs, rebuilt the carb, set the timing, you name it I have done it.. still runs like poop...
go it out on the water and it ran good wide open was able to adjust the high speed needle, idled great adjusted the low speed needle.. anything in between idle and wot it backfires spits and sputters..

So I setup a tank at home and fire it up, I hooked my timing light to it and this is what I found..
Lower cylinder I get a constant fire, the light is steady and on the money no matter where I move the magneto..
Upper cylinder fires all over the place not consistent at all (I thought I had a video but I don't) at idle the light on the upper cylinder is constant like it should be but as soon as you move the mag it starts jumping all over the place and cuts out completely (no light at all) only running on one cylinder..
I had it running on the throttle stop in neutral and it was only running on one cylinder with the other coming in and out, I lifted up on the mag plate and the dead hole came to life.. I let go of the mag plate and it cuts out clear as a bell, lift up on it the dead hole fires, let it go it dies..

I checked the mag and it's seems to be tight on it's mount (well just as tight as the other 10hp I have)
I measured both mag plates I have and both are with in a few thousands, I measure the top of the blocks where the mag rotates and both motors are with a few thousands..

So what I did notice was the mag mount on the 61 10hp (the brass part) was just a little thicker and when I used that mount it seemed to tighten up the play in the mag plate.. I put it back together and it seems way better (watch video and listen closely as I rev it up you can hear it still missing from time to time) at the very end you will see/hear what happens when I lift up on the mag plate.. I thought I had it fixed at the beginning of the video but it stated to skip again at the end..

I have checked the point gap every 10* of the magneto rotation lifting and moving the mag plate and the gap stays constant.. Today I am going to change out everything on the upper hole one piece at a time till it's right..

I was thinking maybe a bad ground but that would effect both cylinders..

just so you know before I changed the mag mount it would cough spit and sputter and most of the time die when you moved the throttle off idle in gear.. In this video it is 100% better so I'm gaining..

at 25 seconds into the video you can hear the top cylinder cut out and when it comes in it's clear we have both cylinders firing..

https://www.youtube.com/watch?v=wryTArPhljM
 
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So you've got it pinned down to the top cylinder NOT firing consistently... plus the mention that you can actually pick up on the mag plate (Armature Plate) to obviously change the point setting to apparently have the top cylinder cut in (firing) as it should.

It would appear that the engine runs lousy due to the many problems that you encountered with it on day one... BUT... at the moment, you have just one to deal with so concentrate on that one.

The "armature plate".... In its flat position, does it actually move sideways... not a rocking motion... just sideways? If it does (worn bearing surface), the armature plate will require replacing (Part #580210) which unfortunately has not been available since 1984. If this condition exists, you're stuck with coming up with the solution.

However, if the above is okay, acceptable, too slight a movement to affect the points and the problem that allows you to "lift" the armature plate that changes the point setting is the rocking motion of the armature plate... do the following.
********************
(Magneto Armature Plate)
(J. Reeves)

If the armature plate has a a loose fitting, wobbling motion (the plate that the points, coils etc are attached to), it is usually caused by a slightly worn support ring. This allows the point setting to change erratically as the armature plate turns.

The cure is to remove the armature plate so that the support which is attached to the powerhead with 4 screws is visible. Then, with a screwdriver and hammer, or some tool of your choosing, and looking straight down at the support ring, make a slight indentation at what would be called the 12, 3, 6, and 9 O'clock positions. Install the armature plate and check for a smooth turning wobble free movement.

You may need to do that procedure a few times to obtain the proper fit (not too tight, not too loose), but it's worth the effort.

Use a small amount of anti corrosive grease between the aluminum ring and the brass support plate and also on the brass bushing of the armature plate when all is well.
********************
Then set the points exactly as I suggest below.
********************
(Point Setting Of Magneto Models)
(J. Reeves)

Set the points as follows. Have the flywheel key aligned with the fiber rubbing portion of the ignition points. Adjust the gap so that a .020 gauge will pass thru but a .022 will not. Should there be any question of the points being dirty (touching the contact with your finger would cause them to be dirty), clean them with a small brush and acetone or lacquer thinner.

NOTE 1: Should the operating cam have a small portion on it with the word "SET" imprinted, align this portion with the fiber rubbing portion instead of the flywheel key.

NOTE 2: Should the cam have the word TOP embossed on the top of it, that is a cam that could be installed upside down and this is simply telling you which side is up. It is not a position where one would set the points.
********************
Once you set the points as above... don't tinker with them, thinking some slight difference in the setting is going to smooth something out... it won't! But it will set up a condition that might bring about a pre-ignition condition that'll melt a aluminum piston... not worth the risk!
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As for the carburetor, I've probably mentioned this previously in another post, however........
********************
(Carburetor Adjustments - Two Adjustable N/Vs)
(J. Reeves)

Initial settings are: Bottom high speed = seat gently, then open 1 turn out. Top slow speed = seat gently, then open 1-1/2 turns.

Setting the high and low needle valves properly:

NOTE: For engines that DO NOT have a shift selection, obviously there is no NEUTRAL position. Simply lower the rpms to the lowest setting to obtain the low speed needle valve adjustment.

(High Speed) Start engine (it will run pretty rough), shift into forward gear, take up to full throttle. In segments of 1/8 turn, waiting for the engine to respond between turns, start turning in the bottom high speed needle valve. You'll reach a point whereas the engine will either start to die out or spit back (sounds like a mild backfire). At that point, back out the needle valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest setting.

(Low Speed) Slow the engine down to where it just stays running. Shift into neutral. Again in segments of 1/8 turns, start to turn the top needle valve in. Wait a few seconds for the engine to respond. As you turn the valve in, the rpms will increase. Lower the rpms again to where the engine will just stay running. Eventually you'll hit the point where the engine wants to die out or it will spit back. Again, at that point, back out the valve 1/4 turn. Within that 1/4 turn, you'll find the smoothest slow speed setting.

When you have finished the above adjustments, you will have no reason `to move them again unless the carburetor fouls/gums up from sitting, in which case you would be required to remove, clean, and rebuild the carburetor anyway.
********************

Yeah, I'm aware that if you keep the engine at a high rpm in a trash can or whatever to adjust the "high speed needle valve", you'll empty the tank of water very quickly. However this adjustment can be made so that you can continue on to adjust the "slow speed needle valve" by doing the following:

Screw in the high speed needle valve gently until it seats, then back it out about 3/8 of a turn, then while in gear, advance the throttle... the engine will of course have a tendency to die out. Back out the HS Needle valve in 1/8 turn segments, trying the full throttle application each time until the engine no longer has a tendency to die out and you find you need to close the throttle quickly (Good enough setting of the HS needle valve to allow a setting of the Slow Speed Needle Valve). The HS setting can be pinpointed later for fuel efficiency while in the water while underway at full throttle.
 
Thanks for the reply...
no side to side play it's actually pretty tight.. it does have some up and down play but not much.. Got the carb dialed in I'm all set there..
I just took it apart and this is what I did..
I changed out the points cam from the 61 10hp I have.. they both looked ok both had some scratches and nicks in them but nothing that would hurt anything..
I checked the point gap turning the armature plate at 10* or so intervals lifting and pushing down on the (armature plate) and nothing moved, gap stayed consistent..
I looked at the inside of the flywheel and from day one it had some scratches where the magnets are, some deeper than others.. I have a bunch of sand paper rolls I use to use back in the day when I would port out small block ford heads so I cleaned up the area, smoothed it out a bit, nothing drastic as to miss with the balance. I also noticed some other areas that looked like it was rubbing on something so I cleaned those areas up a little too.. Like I said nothing drastic as to change the balance..
I set the points to .020 and left them there..

runs like a clock!!
 
I don't know what it should be, but it doesn't hit anywhere and I got at least .015 with the 61 flywheel I cut up.. not much adjustment on these coils ..
20190613_185601_HDR-400.jpg
 
any recommendations on a new pump kit, my housing was a little bumpy, like to get a good one, been having trouble with these aftermarket parts..
 
Pertaining to the coil distance from the flywheel magnets... The engine's running good so I assume you have them where they belong. In any case, the engine's running like a clock you say, so don't touch them.

However, for future reference... a slight bevel exists on the top of the aluminum seat that the coil(s) sits upon. The vertical metal portion of the coil should align with the top inside bevel to create the proper distance between the coil and the flywheel magnets.
 
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