71 Johnson 50 hp

[jbuote]

Hey folks..
​I've had great help here so far, so I started this thread with a general title, so I can keep coming to this one thread for any issues on my engine instead of creating several threads..

​With that, I had my maiden voyage today! lol...
​Put up pics and a summary in the tri-hull forum.. (post # 324)
http://forums.iboats.com/forum/boat...iness-of-the-3v-club-aka-tri-hull-club/page22

​It went pretty well for the most part..
​
​I'm wondering now, how far can I advance the throttle in a test bucket? I have a 42gal(I think it is) tub I can fill and use. Looks like the water would be about 1/2 way up the leg.. Up to now, I've been on muffs when getting her running, so I've NEVER gone past fast idle (start lever) on those..
Todays test, showed that she runs fine at idle, and 1/4 throttle, but gets a skip/miss at about 1/2 throttle. Never got on plane..
​Also had a vibration at that point, but the prop is dinged up a bit. I think it might have some hub slippage too, so I believe a new prop will fix that. Was planning to buy a new prop anyway if this part of the test went well. It did, so I am going to buy a new prop....

Under 1/2 throttle it was smooth...

​I want to test for spark at about 1/2 throttle, and do some other diagnostics at higher RPM, but I can't do all that on the lake in a practical fashion. (yet).
​So, how far can I really go in a test tank? I know full well, that any and all final adjustments MUST be done on the lake, but to get close at home..

​Thoughts?
​Thanks!

 

[JDusza]

Couple things...
I wouldn't go much past start, maybe a little more in a barrel. The engine is not pushing a load and you can over-rev real easy. High speed work should be done on the boat. Sorry.
On an engine stand or in the barrel, use an air gap spark tester to look at spark. Do not run the engine. All you're going to see is a spark. You still won't know if it's timed properly. Gotta believe it is for it's not likely the flywheel has slipped, not if you're running. We know your timer base (trigger) is functional. Check both cylinders. Possible one of them is not firing. Does anything jam the throttle when you increase speed or do you get a nice full throttle range at the hand grip? Nothing jamming the timer base, is there?
After you confirm spark in both cylinders, I would think about your carburetor high speed being a little too lean. Not getting on plane could be low power for lack of fuel.
I would look at fuel delivery.
J

 

[jbuote]

Hey JDusza.. Thanks for the response!

​I had a feeling that might be the case even in a tub of water vs. muffs.. Dang... LOL

​Yeah... I've twice checked spark and compression on this engine.. First when I got it in August last year, and again a couple weeks ago after I found a sheared flywheel key and replaced that.. Both time compression was 170psi both cylinders.
​Spark was tested both times with an open air gap tester.. Jumped 7/16" gap with crisp snap and nice blue spark both cylinders.

​Throttle has free movement full range, and no. I see nothing jamming the timer base. It goes to it's full advance stop and back with the throttle no problem.

​As for not getting on plane, That was mainly MY choice not to push it. Today was the very first time on the water with it, and with the vibration I had when close to 1/2 throttle (Prop I believe..) I didn't want to shake the gearbox apart, so I just puttered. Didn't mean to imply that the engine wouldn't put the boat on plane. I don't know that yet.. I didn't try due to the vibration.

 

[racerone]

Did you use a factory replacement key, yes or no ?

 

[jbuote]

Hey recerone!.. Yes I did. Ordered factory replacement keys (2) so I'd have one on hand if it ever breaks again for any reason.
​I make it a point to always use OEM or third party direct factory replacement parts, unless generic off the shelf parts are outlined and/or called for.

 

[racerone]

The torque is important.----------The flywheel tapers MUST be clean and dry.-------The tapers must be properly fitted.-------That fitting is done with valve grinding compound.-----------The key locates the flywheel for proper timing.--------The flywheel is driven by the properly fitted / locking tapers !!

 

[jbuote]

Yup! That's true... When I did the key, the crankshaft and flywheel tapers looked good, so no obvious issues.
​then I ran a line of Prussian Blue on the crankshaft taper, put on the flywheel, rotated 1 turn (carefully) and the blue showed good mating surfaces.
​Then I cleaned it all up again, so crank and flywheel were degreased and dried thoroughly, then installed flywheel with new key and torqued.
​The torque spec I have is 100-105ft/lbs, so I set my torque wrench to about 102.5ft/lbs, and tightened the nut on.
​Ran the engine for a bit, then re-torqued.

​Now when I use the "Pencil" trick, (don't have a TDC gauge), when I get #1 cyl, (top) to TDC (as close as I can anyway with a pencil), the flywheel TDC mark is lined up with the timing pointer on the cranckcase.

​Do you see anything I did that is either wrong or should not have done?

​Thanks recerone!

 

[jbuote]

Well the weather hasn't been great since Sunday, so I have not been able to do any diagnostics yet.

​My gut is telling me that I may have an intermittent spark issue at higher RPM's.. Runs pretty smooth at idle and about 1/4 throttle.
​I'm thinking I might hook up my timing light and run the engine. Watch the light to see if it appears consistent or if it looks like it's missing a "Flash" (hence spark) now and then. I think I'm also going to run through all the ignition troubleshooting from my manual, and recheck power pack, stator coils etc.. per the manual, and the CDI Electronics troubleshooting guide.

​To that end, I've been looking up different ignition system parts, just to get an idea of availability, cost, etc..
​Certainly won't be buying anything until I've identified something is wrong, but wanted to educate myself as to the parts.

​I found the coil assembly: http://www.iboats.com/IGN-COIL-KIT/d...iew_id.1502760

​What I can't tell is, does this come with the boot and everything I'd need to just "Plug and Play" if you will, or will I need to get the boot and/or other parts also SHOULD I find I end up needing a coil.

​Again.. I'm just trying to educate myself on the parts right now.
​I have no reason yet to suspect I need a coil. Just wondering at this point.

​Thanks!

 

[jbuote]

So a little update..
​I did find the #1 cylinder was misfiring.
​Bought new spark plugs because it really needed them anyway, and also upon closer inspection, I found a crack in the coil casing for the #1 cylinder.
​I have one ordered and waiting for it to come in.
​I'll replace the coil and then see where I'm at..
Hopefully that's all it needs.. lol

Wish I could order more time to work on it and use it though.. haha!! :laugh:

 

[jbuote]

And another update...

​New coil kit has arrived.. Everything I need is in it.. Now to get out there sometime this week and install it..
​Hopefully that takes care of the miss..

Hopefully will get it out on a lake in the next few weeks for a test run.
​Lot's of things going on the next week or so.. Time will be limited, due to other responsibilities, but...

​I'll keep you all posted as things progress..

​Just want to take a moment and express my most sincere thanks to all who have helped me over MANY threads...
​I have a couple topics open at the moment.. This one for the engine, I have one for a prop, and one for a Tow Vehicle, but that seems to have been figured out.. LOL

​I'm going to post short updates in each one for the respective subject, but for now I just figured I'd post the thanks for all of you in one post right here...
​So to all of you, Thank you so much!
​
​For direct help
Such as: F_R , gm280 , boobie , racerone StingRay_90V4 , jimmbo , Maclin , Sea Rider , Scott Danforth , Woodonglass ...

​Also, the indirect help of those I've read posts from, or answers by... Such as cfauvel , Bosunsmate And of COURSE, Joe Reeves ....

​I know I missed a few and I apologize!
​Just know this forum and community has been amazing!
​I only hope I can contribute and help in my ways as best I can as well!

​Thank you!!

Joe

 

[jbuote]

Ok Folks!!

​Finally got the chance to install the new coil...
Quite easy to do, and went off without a hitch.

​Definitely runs better now, without a doubt.. The new tach/hour meter didn't show any jumping RPM's so I know at least #1 is running steady.. Would hope so! That's the coil I replaced.. LOL

​Anyway, seems like there's still a miss now and then, but when I get more time, I'll go back and re-check everything from scratch again.. Spark, Comp, etc...
​Figure it's best to find 1 issue, Fix it, then start over until I find ZERO issues...
One thing at a time.. haha!

Will keep you posted!!

 

[jbuote]

And another update..

​Went out to start the engine again on Monday.. Prepped everything as usual, and everything worked except the starter wouldn't engage..
​Checked things out with my meter, and it all seemed ok.. Then out of nowhere, starter engaged, and she started right up..
Shut it down, then same thing.. Everything worked except the starter.. A few attempts to start, then the electric choke stopped working too.
​Thought I blew the 20amp fuse again, but it turns out it wasn't blown..

​Since then, I've discovered (thanks in large part to F_R) the way I was checking things with my meter, and interpreting results, may not have been correct..
​I'll eat my crow, and admit I had forgotten some basic things about troubleshooting with a multi meter.. :facepalm:

​Having re-read some things, and re-learning, I'm going to check my starting circuit again..
​I MUST have a high resistance somewhere.. All "Bolt On" wire grounds, and wires to terminals have been cleaned.
​I didn't however take off the parts that are grounded through the part, and clean those mating surfaces yet (except for the starter.. It recently was rebuilt with brushes, so I cleaned that up while it was off..)

Will also pay close attention to the safety switch at the powerhead..
​I also discovered that the lower bolt that attaches the bracket for all the coils and the power pack etc.. was missing.. Will replace that too..

​Armed with the re-educated info for multi meter testing, Figure I'll check it all again before doing the cleaning. Hopefully I can identify the culprit area this time...
​Would be nice to find a dirty/corroded area and have testing evidence to back it up for the fix..

​I'm sure so much of this is so basic to most of you, but I'm sharing as I learn and progress.. LOL

​Thanks for indulging this relative newbie!!

 

[jbuote]

Well, Time for another update... lol...

​So I Finally had a little time to go out today and start checking the wiring again..
Decided to start by checking resistance of all the wires from start to finish.

​With the battery disconnected, I started checking from positive batt cable, (end that connects to batt, to end that connects to solenoid). 0 ohms.. (well, 0.2 ohms, but that's the same reading as meter leads touched together, so that's meter resistance.)

​Then checked batt cable at solenoid, to solenoid post red batt cable connects to. 0 ohms.
​Then, solenoid post to fuse. 0 ohms..

​You get the idea.. Checked everything.. Even wire to wire when on the same termination point..

​Found a spot that would occasionally hit 1 MEGA-ohm resistance.. It was on the ground side where the negative batt cable connects to intake for grounding the block.
​The resistance between the tip of the double ended bolt (Part #4 circled in blue in following diagram), to any metal spot on the block itself was about 1Mohm..


Went to take out that bolt and clean up the area..
​The nut seemed like it was loose, but as soon as I thought that, it snapped!! Took virtually NO force at all to snap it.. It was failing somehow already, or PO found the issue, tried to take it out, but felt it "snapping" and stopped. Then left it for me to find.. lol

Now, the exposed side and the nut part of the double sided bolt broke off, leaving just the other stud side stuck in the engine (circled in red.. )

​Time to get some easy-outs, and try.. Worst case would be drill out, clean threads if possible, and re-tap if absolutely necessary..

​Well, on the bright side, I did seem to find an issue! LOL :facepalm:

 

[jimmbo]

If something can break it will. Welcome to Mechanics 101.

 

[jbuote]

Yup! lol... Did auto mechanics for about 4-5 years in my late teens early 20's.. Slowly remembering things long forgotten...
​Including that tidbit jimmbo LOL :laugh:

 

[jbuote]

And the easy outs didn't work... So, drilled it out.. Got a new blind tap in today, so I can re-tap it..
​Hoping to do that tonight or tomorrow and get to lake test it on Sunday..

​Would be nice to see how it runs on the lake with new coil and prop.. (sigh..) lol

 

[jbuote]

FINALLY got to finish up fixing the ground lug.. Night and day difference!! After having the starter checked out earlier and tested good, it still cranked slowly at times..
​Of course, a bad ground will do that.. Starter now cranks as it should!! Never did like the way it was cranking..

​Anyway, Now I have a question.. I found the top coil to have a crack in it, so I replaced it. Haven't gotten to the lake yet for full testing though..
​Question is, Does this sound like it should? Seems to me it's still missing a bit, but it COULD be just mixture settings. I know since replacing the coil, whatever I had it set to is now probably wrong because I set it with a bad coil, but I want to do that adjustment on the lake as it should be done..
​To me it sounds like just about any other 2-Stroke I've ever heard.. (Dirt-bike, weed whacker etc...) BUT.. This is an outboard, and something in my gut says it should run better than this even on muffs...

​Opinions?
Thanks in advance....
(Edit: I start it 3 times in the vid..)

 

[jbuote]

I guess it'd be hard to tell from the vid, and should just get it to the lake and set mixtures again and see where I'm at..
​Have to wait for a prop now though, so it might be a bit... lol

 

[jbuote]

New prop arrived tonight, so will be installing that and hopefully doing a lake test SOON....
​If anyone has any thoughts on the above video before I head to the lake that'd be appreciated..

Otherwise, will just head to lake, set mixtures, idle speed etc.. and see what I have at that point.. lol..

​Thanks again all!!!

 

[jimmbo]

It sounds like it is running a little fast, but that might change once it is in the water. Those little 50s are a little lumpy at idle, just because of the loop charging, porting timing, and big carbs. Both carbs are in sync with each other? Good engine in their day and still are. Yours has an interesting colour scheme