Restoration of 1964 3hp Johnson JH 19A

[Monte NZ]

Hi All
I have had the above motor running successfully, but notice a distinct rattling sound at idle speed, but which goes away as you rev the motor up……….your thoughts regarding this sound would be much appreciated.

As some of you may remember in previous posts, I decided not to dismantle the the power head as the compressions were 65 PSI and should be enough to run, although I appreciate the idling wouldn’t be as good as a motor with higher compression.

Once again, thanks for your help.
Monte NZ

[Monte NZ]

Hi All…..again .
Sorry, I forgot to mention that thanks to a suggestion by a member in previous post, I removed the rewind unit and the noise is still there.

Thanks again.
Monte NZ

[fleetwin]

Monte, I don’t remember seeing/watching the video on this, maybe you can repost.   So, the engine makes the same noise with the recoil removed, so that rules the recoil noise out.  The latest 58 Lightwin I revived has a little rattle at low/idle speeds, and that noise is the throttle lever “rattling up and down” hitting the support and fuel tank, perhaps this is what your noise is.  Keep in mind, these engines only have that way washer that help support the mag plate in place and give it some friction so the throttle lever stays put.

[Monte NZ]

Fleetwin, thanks for your reply. I haven’t put a video up, as I don’t know the procedure. I’m hoping a friend of mine will be able to help me sometime.
I checked out the throttle leaver as you suggested and that isn’t vibrating and touching the tank or the support frame.
The wave washer is doing its job ok, with the mag plate quite fim………..I’m wondering if it could be piston slap or little end rattle?

If it was either of my suggestions, is there any test I can do?

Thanks again for you help Fleetwin.
Monte NZ

[billw]

I guess my approach would be to run it at the speed it rattles at, and push down/lift up/push sideways, everything related to the tank and tank support bracket. If nothing becomes obvious, next step would be to remove the flywheel and check to see if the coil laminations are hitting the rotating magnet in the flywheel. If you don’t know whether any wear marks are old or new, color the ends of the laminations with magic marker, then run it an reinspect. Lastly, if I had a spare lower unit, I would run the motor with that and see if the noise goes away. Strange as it sounds, problems with gear teeth can sometimes telegraph up and sound like they’re coming from the top end.

Long live American manufacturing!

• This reply was modified 3 years, 7 months ago by billw.

[Monte NZ]

Thanks Bill for your reply. Yes , I will do as you suggested. The more I listen, the more I think the rattle is coming from the power head.
I have had the gear box apart and the gears and bearings are in mint condition, with no signs of water in the oil……….in fact, it was a real surprise as the rest of the motor was as rough as guts.
I don’t have a spare lower unit to swap over, so I think I will drop the lower unit and hook up a hose to the cooling pipe and give her a run and see what the results are.
I may be able to spend time on it later this week and I will certainly report back with the results.

Thanks once again for your suggestions.

Monte NZ

[Mumbles]

Has the gearcase ever been off this motor?  If so, it’s quite possible the copper water tube got slightly bent while reinstalling the gearcase and now it’s rubbing on the driveshaft.  The tube is quite soft and bends easily so it might be contacting the shaft due to harmonics at certain RPM’s.

With the powerhead off, you can look right down the exhaust tube to see  it. To straighten them, I’ve used a small wooden dowel and pried the tube closer to the housing than it is to the shaft.  The tube will bend easily if it is burred or corroded and isn’t lubricated while trying to get it inside the rubber grommet on the water pump housing.

Here’s a water tube which was not quite worn all the way thru. If it did wear thru and leaked, the motor would have seriously overheated and have probably been lost.

[Monte NZ]

Thanks Mumbles for your suggestion…….the photo tells it all!
I will certainly check it out and report back. Hopefully I will get a chance to spend time on it later this week.

Thanks again.
Monte NZ

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