Johnson HD-25 "outboard or anchor?"

[Buccaneer]

I went thru three HD-25 2-1/2 hp Johnson’s so far,
and tried starting the third one today.

First one – I flooded bad ! Had to crank in the low speed needle
quite a ways. Finally got it started, but could not proceed tuning,
as it wasn’t pumping water. Ordered new pump rotor.
75 psi T & B cylinders

Second One- Would not fire one lick.
65 psi T&B cylinders.
Spark looked okay with plugs on wires, but
decided to see what it would do with jumping
an "open air gap". Started at 3/8" gap, and
got down to 1/8" or less before it would spark.
Have not proceeded any further on this one.
P.S.- Original condensers still in service.
Coil air gaps at .010

Third one- Started right up, and got it running
good at "Full Speed", down to about "Start"
but can’t get it to run any slower no matter
what combination of adjusting High and Low speed.
Low speed must be open 1/4 to 1/2 turn to get it
to run at Full speed correctly.
65 psi compression T&B

Questions –
Re: #2, How big of an air gap should the HD coils be
able to produce a "spark" ?

Re: 2 & 3, will these little engines run okay on 65 PSI,
or am I wasting my time trying to get the
High and Low speed systems adjusted to run correctly?

Thanks!

Prepare to be boarded!

[steveh]

Buc, your engines should run fine on 65. I have found on mine that there is no "sweet spot" for the high and low speed needles; I need to adjust them a bit if I am running slow or fast. You should be able to get a 1/4" spark. Typical starting point on the needles is 3/8 o a turn on the low speed and 3/4 of a turn on the high speed. Also, the coils and condensers are rarely bad on these motors.

[Buccaneer]

Steve, thanks for the reply. One of the HD mag plates had the little
grounding clips, that I’ve read in the forum recently, and in the
manual, that were part of the "Maverick"? spark system.
I believe the manual showed little capacitors mounted at
the coil base as part of the system too. Mine did not have
the little capacitors. I left the grounding clips in place,
but I’m not sure if it was the HD with the weak spark that had
them!
Are the coils themself different on the old Maverick Spark systems,
and could I have the wrong rotating magnet, or something else
"mis-matched" ?

Prepare to be boarded!

[1946zephyr]

Anchor! The Evinrude Sportsman was ten times more cooperative than the HD’s. Cute little motors though. I completely restored an HD-20.

[1946zephyr]

The best antique Johnsons,in my opinion, were the old A models, as far as ease of operation.

[billw]

quote SteveH:

Buc, your engines should run fine on 65. I have found on mine that there is no “sweet spot” for the high and low speed needles; I need to adjust them a bit if I am running slow or fast. You should be able to get a 1/4″ spark. Typical starting point on the needles is 3/8 o a turn on the low speed and 3/4 of a turn on the high speed. Also, the coils and condensers are rarely bad on these motors.

I agree 100% with all the above and would like to add that they are really nice running motors, when right. FAR from and anchor, IMHO. The 3/4 turn out thing cannot be over emphasized on these and the TD/TNs. This is right out of the manual and makes a world of difference.

Long live American manufacturing!

[Buccaneer]

1946 Zephyr…… Anchors away!, lol
Bill, Will keep "putzing around" on the three HD’s
until I get at least "one" running good!

Prepare to be boarded!

[oltimer]

Buccaneer, long time since we talked. I have had very good luck with the HD25, and every year I get 2 or 3 to work on. 65lbs is ok with these units; but I honestly prefer 70lbs psi. Any lower compression, I find them harder to start or troll down to a crawl. High speed no problem with the lower compression. In all I have worked on, I never seen 80 psi, except when I put in a new set of plus .020 pistons and rings; and that was it. The air gap should be a tite .012; in fact one oldtime dealer friend mentioned closer to .010, but not under. On your pink plunger rods; the flat side to the camshaft only; and that’s a must. The other way will cause problems. Coils are a hit and miss with these, as sometimes they are perfect after sitting outside for years with no "baby care"; but I have lots of good ones on hand, and point sets too, just in case.

[Buccaneer]

Oltimer, I’m working on the HD with the bad spark this morning.
I must have been sleeping when I put the mag plate back together.
I was short one mica washer that should have been between
the two grounding wires at the grounding post.
Going back out to put it back together and see what happens!
Interesting about the plunger rods…… according to you
(at least on the one I got apart now) mine are backwards!
To me, it made sense the way I had them, so the crank cam
wouldn’t catch the sharp edge of the plunger on the flat end,
but rather float around the rounded end of the plunger.
Will report back later, Thanks!

Prepare to be boarded!

[Buccaneer]

Update- "Weak Spark HD #2 runs!
Good spark now that I undid my blunders.
Started first pull. As with #3 HD,
I can’t get it to idle much slower
than the "Start" position. Both of these
were the 65 psi compression units.
Once I get the new pump rotor for #1,
that had 75 psi compression, I’ll see if
it will run slow.
Video of today’s run –
https://youtu.be/tYhQbNPUQeo

Prepare to be boarded!

[Author]

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