Let's get my 1974 Johnson 50HP running!

[dixie460]

Will do, I just ordered a stator and rectifier yesterday. They are both made by CDI since my research on here seems to show that people favor the CDI parts over OEM.

Apparently the rectifier burns up and this causes the stator to overheat and burn up as well. I think I'll be installing a voltmeter and maybe an ammeter as well on my console... that's $200 in parts I don't want to have to replace often and if $20-30 in gauges can prevent it then it's well worth it. Also I see on outboardignition.com (where I ordered the parts) it clearly states NOT to use a maintenance free battery with the rectifier, and that's the kind of battery that came in the boat when I bought it. That's okay though, I'll buy a regular battery with the removable caps because I like them much better.

 

[dixie460]

Okay, stator and rectifier installed! Runs a lot better, idles without stalling, and my brand new non-maintenance-free battery is charging around 16 volts now.
Spark was good on both cylinders. Couldn't really tell in the daylight but it might not have been as bright blue as I like. Could this be weak coils?

Remaining issue is that if I give it full throttle she bogs down a bit, if I go wide open and back off just a little she runs GREAT. Top speed (GPS) is now 23 MPH with 2 people in the boat.

64osby, I've already cleaned the carbs and didn't see any blockages when I had them all apart.

I think after this last thing is cleared up I'll have a great reliable motor!

 

[dixie460]

Hey y'all. Been a few weeks but I didn't forget about this thread of mine. I checked spark and according to my factory Johnson repair manual it should be able to jump a 1/2" gap. Well it barely does that... I'd say in 10 revolutions of the crank I might get one spark that makes it across. Did that for both coils. So I ohm'd out the coils and one was way out of spec, the other was okay but I'm replacing it anyway because they both look original and the other one is probably not far behind as far as failure time goes.

That leaves just two parts of the original ignition system! Power pack and timer base. Now being that this motor is 40+ years old, I doubt it's on it's original power pack but I can't tell how old the thing is and so for $97 I ordered another one. My understanding it that it uses a capacitor to store the energy used to fire the coils. Well capacitors don't last forever and I'd feel better knowing I have a new one installed.

That leaves the timer base. It tested good when I checked it so I'll leave it alone.

I checked compression again just wondering how everything was holding up since I replaced the head gasket and the gauge actually read a couple pounds higher than right after I put the head gasket in. Same gauge and same conditions during test.

And I did a little experiment as well, where I tried the compression test with the throttle open and then again with it closed. Didn't make a damn bit of difference! I was just curious because I know there is a debate on whether or not it affects anything.

And I put a new water pump impeller and wear plate in too. Housing looked okay but I couldn't find a new o-ring for it anywhere. Manual don't show one there, parts diagrams on the net don't show it, I guess it must come with a new housing which by itself is $40. About a year ago I rebuilt the hydraulic power steering pump in my truck. Inside the seal kit there are some o-rings... I remembered one of them being big enough to possibly fit inside that water pump housing. I went to AutoZone and paid less than $10 for the seal kit, took out the second to largest o-ring in there, and it fit right into the pump. Not quite large enough (diameter) to fill the groove but a little QuickSilver Bellows Adhesive fixed that right up. Water tested it and all is well!

I'll be back to hopefully close this thread out and say my motor is running perfectly after I replace the faulty coils.