70s seahorse outboard 20 hp

[chiefcatchemall]

Hey all I am thinking about buying a 1970s seahorse 20 horse. Is there anything in particular I should be looking for before buying this model? Just curious as to what the reputation on these motors are. Thanks in advance, Andrew

 

[chiefcatchemall]

Re: 70s seahorse outboard 20 hp

Obviously a johnson. Didnt state that above, sorry.

 

[RandyJ]

Re: 70s seahorse outboard 20 hp

I've got a 20 and a 25... both have leaky lower units. I hate the sound of them but for the most part they're good running motors. One thing I've noticed in old johnsons like this is that the timing base (ignition plate) is loose on every one I've torn into.

 

[1946Zephyr]

Re: 70s seahorse outboard 20 hp

The old 22 cube motors (18, 20 and 25, 1957 - 1976) are some of the best motors ever built by OMC. If it's in good running condition, I would say buy it. Myself, I would prefere the 1957 - 58 18hp, but the 20's and 25's are still good.

 

[kfa4303]

Re: 70s seahorse outboard 20 hp

I have a '66 20 hp and I like it a lot. Very reliable and easy to work on with lots of available parts and mine is actually pretty quiet. Go figure. If the compression is good on both cylinders (above 65-70 psi and within 10% of each other), I say go for it. All the rest can be fixed for pretty cheap and easy (couple weekends maybe a couple hundred bucks at them most). I would try to get an early 70's model with points and condensers. I think that they went to electronic ignition in the later 70's.

 

[chiefcatchemall]

Re: 70s seahorse outboard 20 hp

Well I bought it. Took a chance. He didnt have a stand for it so he could start it for me. He seems honest about everything. The compression was 108 and 110. Looks like its in great shape. Just changed out the plugs and changed lower gear oil. Gonna go out and give it a shot in the trash can. Couldnt pass up the deal for 300 bucks

 

[chiefcatchemall]

Re: 70s seahorse outboard 20 hp

well its sounds like it wants to run. It will run for about 1 or 2 seconds then make a loud pop and die...Any ideas?

 

[chiefcatchemall]

Re: 70s seahorse outboard 20 hp

The more carb and choke cleaner i sprayed on before I cranked it over the longer it would run. Could this indicate the carb is a little gummed up? Also The model number is 20 R73 A. Is this indicating its a 1973?

 

[kfa4303]

Re: 70s seahorse outboard 20 hp

Hi chief. Yeah sounds like you need to clean/rebuild the carb and I would run some Sea Foam through it too. Should only be about $30 and an afternoon to do both.

 

[chiefcatchemall]

Re: 70s seahorse outboard 20 hp

yup I am going out to take the carb apart right now and clean it up and soak it.

 

[Larry Glady]

Re: 70s seahorse outboard 20 hp

my 77 25hp was like that this spring i cleaned the carbs alittle got it running abit, the more it ranit the better it got