'71 'rude 50, idle questions

[natemeins]

Hey fellas. Wasn't really sure how to title this, hopefully letting me explain the details will help.
New motor to me, I love Johnnyrudes, I had an outstanding little '84 30hp before this one, so I'm kinda familiar with them.
As far as I know on the history: the engine/boat show signs of living in a slip on the lake for many years. The previous owner bought it almost 3 years ago and it has sat dry, with the occasional start. Makes good compression, good spark, turns over with authority. I rebuilt the carbs, set float seat and drop, rebuilt the water pump, flushed/filled gearbox oil, went through the electrical, and gave it a good cleaning up and general maintenance "once over". The coil packs appear to be original, as the high tension wire insulators are cracking, and the metal insert in the plug boots were pretty rusty. Cleaned them up enough to make good contact with new-looking plugs (they're NGK rim-fires, the ones with no electrode tip? My research shows they are adequate alternatives to the proper Champion plugs). Got the engine back together, and did the link & sync. I did NOT touch the timing advance stop or the cam linkage, only adjusted the roller to center on the mark on the cam. I also verified the linkage between the carbs were such that both butterflies were synced properly. Got it in the water, started it up, and adjusted the low speed needles. Idle sounds good and smooth, but throttle lever is pretty high on its travel to maintain idle. High speed is good, transition is good. But if I pull the throttle lever all the way back to its limit the engine will surely die. With the idle stop screw screwed in all the way, the vertical linkage will not touch it and maintain idle. I tried adjusting the black plastic barrel on the throttle cable to no avail. All it did was push the settings further forward to the point I had to bypass the safety start switch just so I could get the throttle high enough to start it cold. Needless to say, I ran out of throttle adjusting barrel threads and I still can't bring the throttle lever all the way back and maintain idle. While the engine was idling properly, I shut it down and had a look at the linkages. The cam is well into its contact with the roller and has in fact started moving the butterflies open. Not much, but they are not fully closed (should they be?)
Am I asking too much from this setup? This is my first time with this type remote (Selectric, single cable for throttle), my little 30 had a simplex type remote which were separate levers for throttle and gear shifting, and the throttle linkage on the engine had an idle limit screw you adjusted on the outside of the cowling where the cable attached. I always had it set so that I could pull the throttle all the way back and it would have a nice idle in gear, perfect for trolling. Shouldn't this remote do the same? Is it possible I still have a circuit clogged on the carbs? Could the idle timing be wrong? Or have I just not set the cable up properly? I did have both ends removed so I could remove the cable from the housing for cleaning and lubrication, when I reinstalled the ends and tightened the grub screws, could I have not set them properly? That seems a stretch but I'm grasping at straws at this point. As I said, the engine will idle and run very well all day, so long as I don't pull the lever back all the way.
Any ideas, suggestions, questions I can answer, or comments would be greatly appreciated. Thanks everyone.

 

[Bosunsmate]

checked the timing? ie tdc on flywheel is at the pointer when top cylinders at tdc

 

[F_R]

Carburetor butterflys should be closed at slow idle. Idle RPM is controlled by the spark advance/retard as you move the throttle lever/timer base. I think you need to double check your link & sync. Especially the length adjustment on the rod between the throttle lever and carburetors cam.

 

[natemeins]

Thanks for the advice, fellas. No, I did not check that the timing pointer coincided with actual TDC, but I will verify that. It appears someone has set it and wanted to make sure wasn't moved in the past due to the white RTV like stuff on the screw holding the pointer.
F_R I think you're probably right. It seems like the timing is too retarded at idle. I looked all over the Seloc (ugh) manual looking for the adjustment for the throttle rod between the vertical linkage and the cam to no avail. I read up on Joe Reeves procedure for a 60hp, but wasn't sure if that was applicable info for the 50hp. Been looking for a correct "link and sync" procedure for the 50 and haven't found it. Any suggestions? Should I get it running, make sure the butterflies stay closed, and move the timing arm until 5 deg. Is reached or a good idle RPM?

 

[F_R]

I only have the manual for 1972, if we can dare think it is the same. It says to adjust the idle speed screw to 3 +/- 1 degrees B.T.D.C. At that setting, the mark on cam should be aligned with center of roller. If not, adjust the yoke on the rod to bring it to compliance. Then readjust idle speed screw to give 700 RPM (maximum) in reverse gear.

Of course, you also have the carburetors' slow speed mixture adjustments to play with.

 

[natemeins]

Thanks for that tidbit. I think I'll dare and try it out. Just so I understand the procedure:
I'll start and warm up the engine. Then I'll adjust the idle stop screw (big straight slotted screw approx. 2" long AFT of the vertical throttle rod) so that the engine is running at 3 deg. BTDC, AND AT THIS SETTING (we haven't spoken of RPMs yet) I adjust the plastic rod end on the horizontal linkage from the vertical throttle rod to the carb sync cam, and set said cam so that it's just touching the carb roller, dead center at the mark on the cam. After this setting, I then adjust the idle stop screw until I obtain 700RPM MAX in reverse gear. Does that sound right?
Just to clarify, I have already adjusted the low speed mixture needles for best rpm, but if the idle timing is out it may change the mixture requirement, so I'll be on the lookout for that.
I assume that the WOT full advance timing is still 19 deg. BTDC? I can't imagine it's wrong but if this is wrong it may be as well.

 

[natemeins]

Wanted to followp with results:
On muffs, I set the timing ring and vertical linkage to 4 degrees, and left the horizontal linkage disconnected from the cam and roller. I set 4 since it was still within the spec and it just seemed better there. Shut it down, adjusted the clevis to slip fit the cam which was synced with the carb butterflies, restarted, and moved idle stop screw to a good sounding and sustaining idle (quite a bit turned in, I'd say all but 1/4" is turned in). Checked mixtures, had to adjust both a hair rich to get best rpm. Took it out to the lake today and she fired right up, but at idle (and I expected this) would not sustain. Back pressure from water. So I adjusted the idle stop screw ALL THE WAY IN, and I was back where I started- pulling throttle all the way back the engine will not hold an idle, and that was in the water in neutral. All other RPM's seemed good.
Some observations:
At idle, the carb throttle bodies are VERY wet. To the point of a little spittle at each stroke. On top of that, it just sounds fat. After doing some more research, I'm convinced my ignition system is very weak for a number of reasons: first, both coil packs are original and the high tension wires are rotted, hard, cracked, and rusty. I'm sure a lot of voltage loss is in them. On top of this, the rectifier I think is on the outs too. One wire is very nearly rotted to extinction. I've repaired it the best it can be, but it's another chink in the armor. Finally, the plugs in it that came with the motor when I bought it, though new, are wrong. They are of the 'V' type rim fire type plugs, and are not suppressed. From what I've read of these plugs, they create terrible idle issues, are cold natured (no heat range), and are not RF suppressed, which could cause other problems. All this to say if the plug needs 30k volts to make a good blue spark, mine is strong enough to MAKE a spark, but not a good one, especially at idle when the engine is doing everything it can to produce the 200VAC to be converted to 30k VDC.
With all this said, I have a new rectifier, two new coil packs, and new PROPER champion plugs coming, they'll be here tomorrow, we'll see what happens.
This is not to say that the link and sync procedure didn't help, I definitely believe it did, but I might be beating a dead horse until I can get the ignition up to snuff. Still, it'll be nice to have this on paper for me or the next person coming to our forum looking for the same advice. So, thanks again everyone for your help. I'll be sure to let you know how it went.

 

[natemeins]

Update: After hours and hours of timing, syncs, electrical chasing, and part swapping, I finally found the little bugger that was giving me all my griefs: believe it or not, the darn spark plug boot on the #1 cylinder! As I'm running it in the test tank, patting myself on the back for fixing the idle problems, it starts it again, but this time I heard the faint but clear sound of high voltage jumping to ground, and at the same time the engine loses one cylinder. Then it comes back in a surge of power. Randomly it's jumping the spark but not at the plug. So I grab the boot to clock it away from the coil and see if the high tension wire is jumping and I get a jolt! Woah. I grab a pair of insulated needle nose piers and as I get closer to the boot to grab it I see the spark jump to my pliers. Of course instantly the engine loses it. I pull away and it comes back. I check the #2 and sure enough it does the same thing! Not as bad but it jumps too! I shut it down, and move the ground wires for the coils, tighten and shorten the high tension leads...do everything I can to keep ANYTHING away from the spark plug boots. I even removed the boots and wiped them clean of residual dielectric grease, and put them back on. Fire it up, now it's worse than ever. Put it in gear and bring power up as if I were taking off on the water. This is where the engine would run fine but now it can't make power before dying off like I hit the kill switch. Completely flustered, I remove both boots and hook the wires up to the plugs. Now it purrs like a kitten, idles beautifully, and makes power at WOT no problem. I've been working on small engines, autos (specifically old VW's) and piston engined aircraft for many years, never have I seen a spark plug boot CONDUCT electricity! Whatever I did this time when I wiped them clean, it caused them to jump from the boot to the flats on the plug itself! So I put the cowling on and took it to the lake. Ran like a champ throughout the rev range all day, all the time without those boots on. What makes it worse is when I replaced both coil packs, of course I got new high tension leads, tips, and new boots. These new boots are conducting electricity?!
So, there it is. Voltage that was supposed to go to the plug was jumping through the boot to a ground, killing the burn in the cylinder. It feels weird to NOT have spark plug boots on it, I'm tempted to run to the parts store and find a pair of lawnmower plug boots or automotive boots, 90 deg of course. Anyone else ever seen such a thing? And why only at idle? Why would it run so well at higher RPM's and not shunt? I theorize that the slower RPM allowed the capacitor in the power pack a longer charge duration, which would create a stronger spark, and at WOT the duration is long enough to make a good spark for combustion but not strong enough to jump through the rubber boot. Thoughts? Should I just run it sans boots? Why would brand new boots cause this?are there boots out there that y'all recommend I put on to keep this from happening?

One other note, especially for other 70's era Johnnyrude owners, pony up and find/get the FACTORY SERVICE MANUAL. I found one in excellent shape on eBay for $20, and it has been invaluable. Where the Seloc manual lacks in detail and missing instructions, the FSM has it all. Was able to PROPERLY set timing and link & sync which did wonders for the little motor. Yes, in regards to troubleshooting the CD ignition, it's out of date. But that info can be had online. Having a proper torque chart, link & sync instructions, carb setup, and colored wiring diagram was worth every penny. It really didn't help me much with finding this problem, but it did help eliminate a lot of variables.
Thanks again to everyone for your help, I hope this is able to help other owners in the future.