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Need Help Identifying 20HP Johnson Year

D

daninski

Member
Just bought the 20 HP and no ID plate so can anyone tell by the pics what year I have as I need to order a few parts. Thanks a lot guys/girls. BTW this is my first post and I hope many more to follow. I belong to a few automotive forums so I'm no stranger to working around motors. Cheers.

Oh no big pictures, sorry.





 
No electric start. I've read that with a simple (ya right) carburetor change if needed I could bump this up to 30hp. Not sure if I'd need to but if it meant getting the boat up and planing with 4 adults in the boat it could be a consideration. So 1980's is the year we're working with so I have a question. It seems for each year there's like 4-6 different model numbers. How relevant is that when ordering parts like say a carb kit. Finally I've seen pics of a 1987 and the paint scheme is some what different so early 80s seems close. Thanks.
 
That 81 motor is not an 81 on that video.-------Look more like the 1980 model in the video.-It is so common that folks do not know the year of a motor.
 
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I sure hope that ad is accurate because I just put an offer in on those decals. lol So the verdict is 1981. Now to order a carb kit and find a manual.
 
racerone said:
I believe the 20 HP model was not offered in every market , therefor it is not listed everywhere.
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I just called my local shop and he can't find a listing for 20hp until around 1985. We were going to order a kit for the first year he has a listing for. Additionally, it seems dremeling out the intake to make the hole larger and rejetting the carb is all you need to do to bump it up to a 30hp. He said he could do the job for about $120 and he'll take the intake off when he dremels it.
 
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So far sites only list 20 hp from 1985. I decided to order the 85 year kit because my daughter wants to go out and fish and if you knew my 7yo daughter you"d know you better get your butt crackin or have a good reason to tell her why we ain't fishin yet. lol
 
They do not list the 20 HP because it was not marketed in the USA but it sure was in Canada.----These motors were the same for many years.------Huge difference in the hole in the intake manifold and carburetor jets is the difference between 20 and 30 HP.-Exhaust tuners are all the same.
 
You'll like those decals if you get them. I put a set from that company on a 1980 115 cowl I restored, and they are great. Just make sure that you don't let the backing stick to itself... it will NOT come apart again.
 

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Yes the sticking backing I understand completely, your engine looks new with the new emblems. I plan to repaint the motor and I'd like to have the cowl done properly in a shop not with rattle cans. I guess I'll have to wait for the kit to come in and see. The guy I spoke with about modifying the carb/intake seemed to know what he was talking about. Very familiar with the process. He said using a template as a guide was a must and not trying to mod the intake unless it's off the motor. Anyway I'll do more research first and possibly source out another intake and carb. Thanks for the advice for sure. I do have a mechanical back ground so separating fact from fiction isn't hard. ;)
 
Ya mines non-thru. So again thanks for all the input here, I'm very surprised I got responses this quick. Of course if someone had an outboard motor compatability chart that would be the cat's a** right. Other forums I'm on we have a good idea what will fit from what years but then I'm not talking as many years as some outboard manufacturers have been around that's for sure. I plan to do a compression test and see where we stand there. I found out 120psi is about the minimum I'm looking for with a maximum 5% split between cylinders. Wish me luck.
 
I have the throttle/drive controls as well but one of them needs a new cable. Not sure if I'll keep the whole steering/motor controls and the pedestal for the steering wheel takes up over half the middle seat. Being a 14ft aluminum boat I'm not sure if I even need the set up. The mechanic I spoke with says he has a line on spare parts and of course there's always Ebay, kijiji and this site. So if I use my Kung Fu pulling arm I should only expect about 90psi? I'll report back here one way or the other. Putting a hitch on my car now then I'll go to my boat and do a compression test and run straight seafoam through the carb and see if that makes any difference.
 
Well I went out today and did a little investigating. Checked the fuel screen for blockage then added sea foam to a cup of gas/oil. After a few minutes I added that to the tank of gas with more Seafoam and took the boat out. No change. My question is under what conditions should I be adjusting the Lean/Rich screw. I originally adjusted it at idle.
 
The high speed jet is fixed and not adjustable.---The low speed jet is adjustable and adjusted at low speeds for smoothest running.-Adjust it for smoothest running and a slight stumble on rapid acceleration is OK.
 
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