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fleetwin.
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May 28, 2017 at 7:41 pm #58539
Another question then:
The plugs I found in the motor are L77JC4–new looking. According to the "shop evinrude" site the correct plug is QL77J4C. I believe the Q means a resistor plug. There is also a surface gap plug approved: L76V. The black box installed is "Bombardier amplifier assembly" P/N 389550, Wabash Magnetics. I know resistor plugs can play a role in suppressing electrical noise and transients, so am wondering if the "Q" is necessary/important.
I also found this from Champion: ""Outboard marine Capacitive Discharge Ignition systems (CDI) such as used on some Johnson and Evinrude marine engines require a special inductive type resistor spark plug (such as a Champion Q-type). This is because these type of ignitions systems produces less voltage; use of non-inductive type plugs can cause misfires and poor performance."
Guidance from the experts?
May 28, 2017 at 11:57 pm #58551Compression: Throttles tied open, all plugs out, oil can shot of oil in each cylinder:
#1 126
#2 123
#3 125
#4 122I don’t know what’s normal for these.
On the other hand, I can’t get it to shift, at least not at cranking speed. I tried thumping on the gearcase with a plastic hammer while cranking. Refined technique, no? It won’d move out of forward, at least at cranking speed.\
How much of a project is it to open and reassemble the gearcase of one of these?
May 29, 2017 at 12:14 am #58554Those L77JC4 (non-resistor) plugs were a life-saver when they came out back in the day. Actually they were L77J4J back then, if I remember correctly. Yes, they have now been replaced by the Q plugs which have inductive suppressors instead of resistors. In my not so humble opinion, the surface gap plugs don’t even make good landfill.
It should shift at cranking speed.
May 29, 2017 at 12:21 am #58555OK, I think you better slow down a bit….Please don’t rip that thing apart, I don’t think there is much wrong with it.
First, the gearcase. The dark colored lube is probably the old OMC type C, which was dark. The newer OMC premium blend lube is gold in color. I don’t know if I would tear the gearcase down because of a few drops of water. Did you refill with OMC premium blend? If so, please know the gearcase will not shift without 12 volts being applied to one/both of the shift leads coming up from the gearcase. And, the gearcase will not shift unless the driveshaft is spinning. The driveshaft must be spinning to turn the oil pump which develops oil pressure to push the clutch dog out of forward gear. The control box in your picture will not work on your engine.
The compression seems normal for that engine. You do not need to use the Q plugs on this engine, the regular L77JC4 plugs will work fine. Champions notes refer to ignition systems used on much newer engines. Does the engine have spark? You will have to run a positive jumper lead to the powerpack terminal on the board so it is powered up while cranking to see if it has spark.May 29, 2017 at 3:21 am #58567quote fleetwin:OK, I think you better slow down a bit….Please don’t rip that thing apart, I don’t think there is much wrong with it.Maybe so, but I proceeded carefully in testing the solenoids electrically, and the thing would not shift while cranking, with leads energized. It just stayed in forward.
First, the gearcase. The dark colored lube is probably the old OMC type C, which was dark. The newer OMC premium blend lube is gold in color. I don’t know if I would tear the gearcase down because of a few drops of water.
Neither would I. But the motor isn’t very useful if it won’t shift.
Did you refill with OMC premium blend?
No, I filled it with some hydrostatic transmission fluid I had on hand. I thought a flush and testing might be in order before buying the expensive stuff.
If so, please know the gearcase will not shift without 12 volts being applied to one/both of the shift leads coming up from the gearcase. And, the gearcase will not shift unless the driveshaft is spinning. The driveshaft must be spinning to turn the oil pump which develops oil pressure to push the clutch dog out of forward gear.
Yes. As far as I know there are no test ports on this box to check pressures, so my diagnostic possibilities are limited.
The control box in your picture will not work on your engine.
Yes.
The compression seems normal for that engine. You do not need to use the Q plugs on this engine, the regular L77JC4 plugs will work fine. Champions notes refer to ignition systems used on much newer engines.
Good. Thanks.
Does the engine have spark? You will have to run a positive jumper lead to the powerpack terminal on the board so it is powered up while cranking to see if it has spark.
Don’t know. Have left fuel and spark to last because I know I can get them working if the powerhead and gearcase are serviceable. But I would like to know what that "amplifier" actually is.
Thanks!
Alan
May 29, 2017 at 11:29 am #58575The amplifier takes 12V from the battery and boosts (amplifies) it to about 300V, and the 300V is stored in a capacitor until time to fire.
The breaker points tell it when to fire. When a set of points opens, it is sensed by the amplifier and it discharges that stored 300V to the coil primary. That 300V discharge is the "CD" in "Capacitor Discharge Ignition".
Like any other coil, the primary winding induces a high voltage in the secondary, which is sent to the spark plug.The advantage is the coil is operating on 300V pulses instead of the normal 6V on a conventional automotive system. The pulses are much faster and give a very high voltage and fast spark. This helps the plugs to fire even if gooped up with carbon and oil.
Unfortunately, they coupled it with a crappy distributor.
BTW, the system is perfectly capable of running backwards. That reverse cut-out ring we’ve mentioned prevents that.
May 29, 2017 at 1:50 pm #58580So it’s a "normal" capacitive discharge ignition….
By the way, what’s the best way to do the flywheel nut on these? No obvious way to use a strap wrench. Maybe my impact wrench will take it off, but torquing it on will require holding.I’m hung up on the non-shifting.
May 29, 2017 at 1:58 pm #58582"BTW, the system is perfectly capable of running backwards. That reverse cut-out ring we’ve mentioned prevents that."
Hmmm, that could be the solution to the gearcase problem: Convert it into a dockbuster.
May 29, 2017 at 5:50 pm #58586quote amuller:So it’s a “normal” capacitive discharge ignition….
By the way, what’s the best way to do the flywheel nut on these? No obvious way to use a strap wrench. Maybe my impact wrench will take it off, but torquing it on will require holding.Get a better strap wrench. Seriously, you should be able to use it. Or you could get one of those automotive flywheel turner tools. Or you could do like the rest of us and stick a big screwdriver between the flywheel gear and starter pinion. But you will never get us to admit that. No Sir. 😯
May 29, 2017 at 6:06 pm #58587I downloaded an OMC manual which is full of interesting advice and opinions, some of which make good sense, others …… The author specifically warns against the big screwdriver/Starter pinion approach…..
Hmmm, I have these pipe tongs: Chain loop and about a four foot handle. That ought to do it, no?
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