Questions on '82 & '71 25HP Johnson's

I am currently working on an 82 Johnson 25hp and a 71 Johnson 25 hp. Both are tiller handle. I?m not mechanically handicapped but I haven?t done much work on outboard motors. I?ve been around them plenty but never owned one and quite frankly as long as they started and ran I didn?t much think about it. Geez that statement sounds like my wife talking about her car. Most of my experience is restoring cars?as a hobby?.not professionally.

Questions are:

The 82 has a ?tell-tale? water stream squirting to show the water pump is working. Should this be a constant stream or can it intermittently stop and start. It squirts the vast majority of the time. I?ve only run this in a barrel so far.

The 71 has no ?tell-tale? squirting at all. Does this motor not have one or is the water pump not functioning. It runs fine, but while idling in the barrel it seems to try to jump into gear and then goes back to neutral. It works fine when in forward gear, haven?t tried reverse. Is this a linkage problem or the lower unit on its way out?

Lastly, when looking for parts motors (Johnson or Evinrude) is there a span of years that are basically the same and parts mostly would interchange. The does appear to be difference between the 82 and the 71.

Thanks Rick

Re: Questions on '82 & '71 25HP Johnson's

The tell-tale on the 82 should be a steady stream, will pick up engine rpm, but should be a steady stream at idle. The stream of water is coming from the water pump, if it stops and starts I would check and make sure the tube and fitting is not partically plugged, if no blockage is found I would check the water pump itself.
The 71 does not have a tell-tale, you could install one if you wanted to. You can monitor the exhaust outlet for water pump operation.
Check the lower ouit oil for water and/or metal particles, make sure the linkage is adjusted properly. Sometimes running an engine in a barrel can give you strange results, how does it work in the water?
I think you are going to find quite a bit of difference between the two engines, look at the parts breakdown for each and compare some part numbers.