Johnson Seahorse 10 HP

[vdubber87]

Hi guys. I am about to go take a look at a Johnson Seahorse 10Hp OD-20 motor. Can someone tell me what year this motor was made in, and is it good in general or not? Thanks

 

[jbjennings]

Re: Johnson Seahorse 10 HP

It's a 1960 QD-20. They are excellent motors. You might want to check the lower unit for water by pulling the lower unit drain screw. Just crack it when it's sitting like it would be on the boat and if any water is in it, you'll see it right away. About their only weakness is folks running them with water in the lower unit.
Hope you find a good one,
JBJ

 

[F_R]

Re: Johnson Seahorse 10 HP

I agree, they are excellent motors, subject to the ills of wear and tear, and age.

An age problem could be the magneto coils. They are usually bad unless they have already been replaced. The owner probably won't let you tear into it to check them, but at least ask if they have been replaced. If he dummies up, that can be a price talking point. They aren't a big deal to replace, but allow about $40 for parts.

Another wear and tear item unique to the 10hp is they would beat the wrist pins out of the pistons. To check this, remove the spark plugs and stick a screwdriver in the holes and follow the piston up and down while slowly turning the flywheel (don't push on the screwdriver, just follow the piston). When the piston is about halfway on it's downstroke, stop turning the flywheel, then give a push on the screwdriver. If it moves more than a microscopic bit with a clunking sound, the wrist pin is loose. They can get amazingly loose, but sooner or later they have to be dealt with. Repair involves new pistons, wrist pins AND connecting rods.

 

[starsnstripers]

Re: Johnson Seahorse 10 HP

The QD 20 Is a 1959 10hp

 

[samo_ott]

Re: Johnson Seahorse 10 HP

Yep, it's a '59. The first year of the fibreglass cowling. Oil mixture is 24:1.

There is a peep hole in the flywheel where you can see the coils once you remove the pull starter. That's the easy way to check the coils.

 

[jonesg]

Re: Johnson Seahorse 10 HP

I have the same engine 59 10hp, I'm changing the coils now.
Seems simple enough compared to the big modern engines, you'll need a puller to get the flywheel off and hardened bolts , otherwise everything has been straightfwd, it uses a pressure fuel tank, 2 lines, unless converted to a pump.

 

[byrdman4u]

Moring all can anyone tell the torque on QD-21 1960 seahores johnson lower unit four 1/4 bolts is it 60 lbs per inch??? Not sure thanks all

 

[byrdman4u]

Can any one tell me the torque on the four 1/4 bolts on the lower unti is it 60 lbs. 1960 seahorse johnson 10 p QD-21

 

[WIMUSKY]

@byrdman4u

Please start your own Topic...

Thanks
wimusky