1969 Johnson misses no power

" I just aquired this motor an

" I just aquired this motor and when test started it ran ok. However, after installing it on my boat it is popping and backfiring. I have o/h the carbs and replaced the dist cap and rotor. Some improvement but not quite right. I just found that the insulation on the wiring to the sensor inside the dist is falling apart and the wires shorting together. Will this cause a miss? I would have thought that the motor wouldn't run at all. Any other thoughts or suggestions would be appreciated. Thanks, Jeff yoscovits. "

jeff>i would think that t

jeff>i would think that those wires have a lot to do with it

" Jeff, What horsepower is you

" Jeff, What horsepower is your motor? "

" Jeffrey, it's a 115 hp.

" Jeffrey, it's a 115 hp. I started it today and it still isn't right. It seems the #4 cylinder isn't contributing. Compression was checked and at 135 for all cylinders. I see in the service manual that the fuel pump diaphragm could have a pinhole in it causing #4 to run rich. I disassembled the pump and didn't see any holes. Is this still a possibility even though it's not visible? Johnson dealer advised to connect timing light to each spark plug wire to see if I lose spark. I tried this and had no strobe from any wires. Possible that my light was inop though. I'll try another light tomorrow. In the meantime the walleyes and perch are about to start running and I would really like to get a few dinners. Thanks, Jeff. "

" Jeff, I am no expert with th

" Jeff, I am no expert with the bigger OMC motors. I try to stick with two cylinder motor repair work. ( motors I can lift) However, my experience with the smaller OMC's would tell me the following: If the popping and coughing is occuring at or near idle speeds it may be one or both of the following: The engine may be running too LEAN at idle, try richening the idle mixture jets. Or, the carburator to spark advance timing is improperly adjusted, I would check with a service manual for proper synchronization. Usually if that needs adjustment, they need LESS carburator opening at a given thottle setting. I hope one of these adjustments will get you back out there.
Jeffery. "

"I have checked and double che

"I have checked and double checked the carb mixtures. Removed the carbs to recheck. removed the reed block, looked like new. Removed the #4 cyl bypass cover, piston skirt looks excellent, piston top looks very clean. Rechecked distributor wiring and installation, ok. Unwrapped motor wiring harness to look for any faulty wires, all ok. Synchronization adjustment appears ok. I am at a total loss as to the cause of this miss. Someone suggested a leaking bottom crank seal. Any thoughts on this? Any suggestions or advice is appreciated. Thanks, Jeff.P.S. Feel free to e-mail me direct at [email protected]."

"You've mentioned that you

"You've mentioned that you have 135 psi on all cylinders but you haven't said if you've checked the spark or not. The spark on that engine (with the s/plugs out) should jump a 1/4" gap on all cylinders..... Does it? And do you still have that 135 psi on all cylinders?

Joe "

" I did test the spark. I do h

" I did test the spark. I do have more than 1/4 in spark. Spark and compression were also tested at the Johnson dealer with a spark tester. He stated the spark was good. This was done simultaneously. Dealer declined to work on motor due to prior repairs performed by others which included disconnecting the safety or clipper switch. Could this have any effect on my problem? I inspected the piston through the bypass port at his suggestion. He stated the skirt may be galled causing the concern. He said he didn't want to diag and bill for 2 hrs labor and still have me left with problems. I can understand that as that is how I feel in the auto repair business.This motor has more of my hair graying and I'm worried it may also be starting to fall out too. Thanks for any help, Jeff. "

"Jeff.... Back when that engin

"Jeff.... Back when that engine was new, we encountered quite a few that wouldn't run properly on the called for surface gap s/plugs. Installing Champion L77J4 or L77JC4 s/plugs, gapping them at .030 cured the problem.

I wonder if you may have overlooked cleaning the brass fixed high speed jet in the lower carburetor (port side) that would feed #4 cylinder. If those high speed jets (4) weren't removed and cleaned thoroughly, that would have a massive effect on the engine as the fuel must flow through them first before gaining entrance to any other aspect of the carburetors.

Joe"

" Joe, I didn't physically

" Joe, I didn't physically remove the jets to clean them,but I did heavily spray carb cleaner and air through them. They appear to be clean, but maybe I will need to R&R them and clean them that way. I have installed new QL77JC4 spark plugs gapped at .030. Thanks, I'll clean those jets, Jeff. "

" I removed all the high speed

" I removed all the high speed jets and cleaned them. I didn't really see any gunk on them, though. I replaced the #4 plug w/ another new one and the #4 cyl is now working. The engine still runs rough and the idle speed seems higher than it should be. I don't have a tach hooked up. I'm just calling that by ear. The rpm drop when pulling the #3 and #4 plug wires is not as much as #1 and #2. Spraying fuel mix into carb throats has no effect. Could you please give me a brief explanation of how the CD ignition works on this motor. I guess I'm too used to automotive electronic ignition systems. Do I need a certain type of tach for this motor. Thanks for the help, Jeff. "

"Jeff... The ignition system,

"Jeff... The ignition system, without getting into the deep portion of it is: The battery must be in top condition, and be at least a 70amp hour battery to supply proper voltage to the pack, otherwise damage to the pack might occur. Voltage is being supplied to the pack and stored in a capacitor. The sensors in the timer base, trigered by the magnets at the center of the flywheel, supply voltage that in turn trigger a electronic switch in the pack which throws the stored voltage to the coil. The coil magnifies the voltage higher and transfers it to the rotor, then to the distributor cap, s/plug wires, etc.

You've stated that you do have spark on all four (4) cyls that will jump a 1/4" gap. It doesn't sound like you have a ignition problem.

The fact that you have made a gain in performance by cleaning/changing the h/s jet(s) in the bottom carb suggests to me that something is being overlooked in the fuel department. You made the statement "The rpm drop when pulling the #3 and #4 plug wires is not as much as #1 and #2". Just so we're not getting our wires crossed here, the cylinders are number as below when standing in back of the engine.
..........1
2
..........3
4
Cylinders #1 and #2 run on the top carb. Cylinders #3 and #4 run on the bottom carb. The lower response on #3 and #4 indicate that either there is something wrong with the bottom carb or it is out of adjustment on the adjustable slow speed needle valves. It's highly unlikely that two (2) leaf plate (reed) assys would be faulty or that the ignition would fail slightly on the two bottom cylinders.

If you're absolutely sure that the bottom carb is now completely clean, and that the linkages connecting the two carbs are as they should be (one doesn't open before the other), try adjusting the slow speed valves as follows.

First, if you haven't already, install new "red" valve retainers in the front of the carbs so that the needle valves can't viberate out of adjustment. These are OMC part # 315232. With these retainers, there is no need to have all that interconnecting wild linkage entwined between all four valves (with the red retainers, they won't move by themselves).

Gently seat all four (4) needle valves, then back them all out one and one half turn (1 1/2). Start the engine and set the idle to a point where the engine will stay running. Being in the boat, facing the carburetors, start with the top left, then top right, then bottom left, then bottom right needle valve.
1...2
3...4
Slowly in segments of 1/8 turn, turn the valve in and wait a few seconds for the engine to respond. Continue this action until you reach a point whereas the engine either spits back (sounds like a mild backfire) or it starts to die out. At that point, back that needle valve out approximately 1/4 turn. Within that 1/4 turn, you will find the smoothest setting. As you turn the valve in, the rpms will climb... drop the rpms (idle) to where you had it when you originally started this process, otherwise you'll end up with a screaming engine.

Repeat this process (adjustment) on all four (4) adjustable slow speed needle valves. You may need to repeat this process to double check yourself as at times, one cylinder may affect the other slightly. Good luck.

Joe"

The tachometer.....(slipp

The tachometer.....(slipped my mind) Your engine requires a tachometer that will operate off the charging system that has a six (6) pulse setup. Any marine dealership should have these in stock.

Joe

" Joe, I readjusted the low sp

" Joe, I readjusted the low speed idle screws. there is a definite improvement. I now have an equal drop from cyl to cyl, but the motor still runs rough. I tried spraying fuel into the carb throats one at a time. This caused the motor to stumble evenly on all 4 cyls. Could I maybe have a timing problem? I think we're getting close to solving this. You didn't mention in your description if the power pack controls timing. Is there a base timing adjustment? It just seems to me the way this thing runs that it's firing at the wrong time. Thanks, Jeff. "

"Jeff... There is a screw with

"Jeff... There is a screw with a rubber stop that the timer base hits up against but that is the full spark advance setting which simply put, keeps the timing from advancing beyond a certain point at full throttle. That would have nothing to do with your problem. And no, the pack doesn't control the timing.

If that engine has points, they set on the high lobe at .010 . If it has a sensor, it sets at .028 . (I can't recall which it has).

Check the flywheel key. It must be perfect as the slighest wear will affect the timing (OMC part # 307408). The outer edge of the flywheel key must be vertical (not in line with the crankshaft taper).

Is that pack the original one or has it been replaced? I'm wondering if possibly your engine may have the wrong metal rotor for whatever pack you have if your engine uses a sensor. Describe the pack as best you can, and give me the measurement of the gap that exists in the metal rotor.... if it exists.

Joe"

" Joe, I gues I totally neglec

" Joe, I gues I totally neglected to post an event that took place on Monday prior to my Thur 8/30 post. I decided to replace the #4 plug w/ another new Ql77JC4 plug.After doing so and starting the motor, it ran rough, popping and stalling. When cranking to restart after a stall, the motor misfired and sheared the flywheel key.The key that was there was thinner than the groove in the shaft. I obtained several automotive keys from work and matched one up w/ the old one. It sounds like a trip to the Johnson dealer may be in order. This sounds very critical.As far as the pack goes, It is a black metal box, 4x6 in. w/ 6 wires, blue, purple,2 black and 2 black and white.If you mean the trigger rotor, it's approx 2" in diameter, it has four windows approx 3/8" across. I have it adjusted to .028. You may have hit it right on the nose with the flywheel key. Will check out tomorrow and let you know. Thanks, Jeff Yoscovits. "

" In your last post you mentio

" In your last post you mentioned: "I gues I totally neglected to post an event that took place on Monday prior to my Thur 8/30 post When cranking to restart after a stall, the motor misfired and sheared the flywheel key."

Yea, that would've narrowed it down somewhat. If any metal was smeared around the flywheel or crankshaft taper, all of it will need to be cleaned thoroughly or you'll shear another key. The flywheel nut must be torqued to 105 foot pounds. "

" I replaced the key tonight.

" I replaced the key tonight. Too late to fire it up in the driveway. I cleaned the flywheel and the crank up w/ emery cloth.Looking at my Seloc manual, the wiring diagram only shows 4 wires to the power pack. It doesnt show a blk wire going to case ground. It also doesn't show the other black wire. I'll try it out in the AM and let you know how it goes. Thanks, Jeff. "

" Hi all, I'm happy to say

" Hi all, I'm happy to say that this problem has been solved. I replaced the crankshaft/flywheel key with a new one and it appears to have been the main culprit. Thanks Joe Reeves for hanging with me on this. When you mentioned how critical the key was, I realized that when I replaced the cap and rotor, I did notice a lot of movement of the flywheel around the key. When it sheared, I just replaced it with one of the same thickness. I took that one out and replaced it with one the fit tight in the flywheel and on the crank. I took the boat out today on the Detroit River and the motor just purred. One question I do have however, is, under hard throttle the boat wants to pull hard to the right and the left side seems to dip. Any suggestionson that? Otherwise, I'm a very happy boater today. Thanks to all that helped, especially you Joe. I'm a Lincoln/Mercury tech so if there's anything I can help you guys with, don't hesitate to send an email. Thanks again, Jeff Yoscovits. "

"Jeff... You'll see a trim

"Jeff... You'll see a trim tab on the bottom of the cavitation plate (just above the prop). Move that tab slightly IN THE DIRECTION OF THE PULLING direction. Your boat wants to pull to the right so move the tab to the right. Before moving it, take a screwdriver (or something) and scribe a line on the tab to the plate it's on. This gives you a reference as to how far you moved it, in which direction etc. Now.... how do I remove the head rests on my wifes 1989 Ford Crown Victoria? Reply to that via e-mail so we don't take up any more room here on non boating issues. [email protected]

Joe"

" Joe, I'll get back with

" Joe, I'll get back with you soon on that headrest removal. I'd really like to thank you for all your help. This has been a real 2 stroke education for me. I actually wouldn't mind getting into the business. Thanks again, Jeff Yoscovits. "