new to me 1970 ish Johnson 20 hp

[TN-25]

I got a 20 hp johnson outboard the other day that had been sitting in a garage for a couple years. I have already cleaned/rebuilt the carb and water pump. The compression was 126 in both cylinders and their was spark but it just didn't seem very strong had a gap tester and it was jumping the 5/16 gap i have read about. I took it out on the water today and had a terrible time getting it started I did get it started with a shot of starting fluid which i know is a nono but i did it. It did run fairly well once started. anyways i was wandering what you guys thought about the starting thing also i am missing a piece on the carb that controls the tuning needle. Attached is a picture of the motor and the front of the carb some sort of a cam shaped nut goes on the end of that brass piece i believe if you know what that is and where i can find one that would be really helpful along with a possible year and any thoughts on the stating issue

The front of the pan appears to be curved, something that was last done in 1970. Within that range, 1967 was the year they were a medium green; all others were dark green. I would agree that it looks like a 1967 20.

 

[fishermanof93]

Starts and runs like a dream it's still not quite deep enough though any idea what the optimal depth is ? When I get over 8mph the water doesn't crash into the propeller quik enough

 

[racerone]

Motors in the 20 hp category come in 2 flavours , short shaft and long shaft.-----------Boats come in 2 flavours as well.-----------A 15" high transom is called a short shaft and a 20" high transom takes a long shaft motor.------------So how high is the back of your boat and is your motor a long or short shaft model ?------Is there a 5" spacer between the lower unit and the exhaust housing ?------Post picture of that area as it can be instantly regonized as short or long shaft.

 

[fishermanof93]

No Title

There was. 9.5 on it and the boat was notched so this fit down in that same notch

 

[fishermanof93]

its definitely a short shaft. so are u saying the transom needs to be 15 in?

 

[pckeen]

Yes - or close to it - transoms are not always exactly 15 inches - if the transom was 16" you would be OK - but if the transom was 20" you need a long shaft motor.

 

[fishermanof93]

ok I will cut the transom down some then thanks for the info

 

[Bosunsmate]

ok I will cut the transom down some then thanks for the info

Being a 20hp id just bolt on an outboard bracket. That way if you ever get a long shaft you just unbolt the bracket and epoxy up the holes

 

[fishermanof93]

got her al mounted up and ready to get to the water. out a new seal kit in the gear case as I noticed a significant. or significant enough I wanted to fix it, amount of water in my oil after my first trip. I am not doing a 100% original rebuild on this or even making a show room piece however I want it to look nice and close to original. I am going to put some decals on the engine cover from an older Johnson cause I like the look better and want to paint the lower unit back to original or close to original color. is the color of the motor the color the lower unit should be or is it completely different. again if its close and in a can at lowes that's fine with me since its not going to be original or showroom thanks again in advance.

P.S. here is the new stance on the boat.

 

[fishermanof93]

got her out last weekend finally and found a few more smaller problems, nothing I cant fix, was curious though if there is a way to tighten the throttle control on the tiller handle cause I have to hold it in the start position while pulling the cord which is a pain also it wont hold its position at idle so if I just let it idle to get something out of the front of the boat it turns itself off. any information is helpful thanks in advance