Evinrude/ Johnson 20hp to 30/35 conversion HELP!!

[Rangernick]

Hey All

Im new to the forum and im sorry if im beating a dead horse here but I am working on converting my 1993 Johnson 20hp (J20CRLETS) to the 30/35 carb and intake. I could really use some help figuring out what years are compatible. I have read through every forum I can and most of the suggestions are just look at marineengine.com and such and compare part numbers. Im really racking my head trying to figure out what I need to compare and such. I could really use some help figuring what numbers will fit my 93'. I have found a guy with a intake and a carb off of a 78' 35hp he claims part #3243391 for the carb and #356792 for the intake. When I look up the carb part number I cant get anything to even come up!? Will a 78' work? Im pretty lost here and desperately trying to learn! Also are evinrude and johnson interchangeable these years? If anyone flat out knows what years will work with my 93' that would be amazing.

Thank you for any help ahead of time. It seems most of the conversion posts are quite old now so I hope im not annoying anyone! Boat is a old 1448 Jon with pods and some upgrades!

 

[racerone]

Your location ?

 

[Rangernick]

Spokane, Washington

 

[racerone]

Part numbers are usually 6 digits.----So review that part #

 

[Rangernick]

Good advice! Thank you!

 

[Sea Rider]

Are all 3 motors same CC displacement to start with ? if not can't convert as will be different marine animals.

Happy Boating​

 

[racerone]

Since 1977 to end of production in 2005 ( ? ) the 2 cylinder 20 / 25 / 30 / 35 HP model have used the same design block and same displacement.----It is 31.8 cubic inches or 521cc for the metric folks.------Remember the early 35 was powerhead rated and later 30 HP was prop rated I believe.----And Johnson models are often white paint and some days they used blue paint for Evinrude models !

 

[Rangernick]

Since 1977 to end of production in 2005 ( ? ) the 2 cylinder 20 / 25 / 30 / 35 HP model have used the same design block and same displacement.----It is 31.8 cubic inches or 521cc for the metric folks.------Remember the early 35 was powerhead rated and later 30 HP was prop rated I believe.----And Johnson models are often white paint and some days they used blue paint for Evinrude models !

Thank you for that knowledge. I was thinking similarly. I believe what I need to find is simply a 30/35 carb with the same choke setup as mine. Steal the carb, intake and possibly timing and ill be set. Now I need to figure what years used the same choke setup as mine.

 

[racerone]

The electric primer valve is a far better set-up than a choke flapper.-----And an easy install if you understand how it works.

 

[Rangernick]

The electric primer valve is a far better set-up than a choke flapper.-----And an easy install if you understand how it works.

The "choke" set up on my current motor basically just shoots a shot of fuel into the intake? I'm not sure what style that is called but I should be on the lookout for a electric primer valve set up then?

 

[racerone]

The electric primer has a red lever on it for manual operation.-----Or the manual primer shoots fuel in when operated.----All very easy if you understand how they work.-----The electric primer was used on electric start motors from 9.9 to 300 HP.----A wonderful item it is.

 

[Rangernick]

Very good to know. My motor is a pull start

 

[Rangernick]

#396790 for the intake and #439377/ #435376 is what I'm on the hunt for now I believe! Ill keep the post up to date once I know more!

 

[jasper60103]

In my opinion, Johny25 has the best documented and helpful thread on the subject matter. See link below. Too bad he moved on years ago. Good luck.

80's johnson/evinrude 25hp to 30-35hp conversion with pics

Ok I know this thread has been rehashed several times but I decided to put pics of the modification up and point out the differences between the 25hp and 35hp. Although the 35 became the 30 after the prop HP rating in 85'. First is the carburetor difference: The 25hp is a 1988 and the 35hp is...

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