LOWER UNIT 50HP & 70HP SWAP

[markhorton1979]

I have a 1974 Johnson 50hp model #50ESL74M mech shift and the shift rod is froze. My dealer says I need a new lower unit. I found one on ebay and the seller says it will work but it is off of a 1974 70hp with model #70ESL74 Can anyone confirm that this will work? E-mail me if possible. markandkatrina@msn.com Thanks in advance.

 

[jimmbo]

Re: LOWER UNIT 50HP & 70HP SWAP

gear ratios are different for one

 

[ob]

Re: LOWER UNIT 50HP & 70HP SWAP

Yep ,they're the same.P/N for gear case w/bearings is 0385560.<br /><br />edit:jimmbo is correct.Fwd, rev gears,and pinion are different ,but the lower unit case is identical.

 

[markhorton1979]

Re: LOWER UNIT 50HP & 70HP SWAP

So will this unit work or are the gear ratios too big of a factor? Will it dramaticly reduce my take off speed or is it that noticable? Also will it just bolt directly up to my 50? Or should I wait for a 50 hp unit to come along?

 

[Chinewalker]

Re: LOWER UNIT 50HP & 70HP SWAP

I'm pretty sure the driveshafts are different, too - different splines at top. The 50s use a fine spline, while the 70s used a 4-sided spline...<br />- Scott

 

[phatmanmike]

Re: LOWER UNIT 50HP & 70HP SWAP

why not repair the one you have? sounds like your dealer is trying to sell you parts!<br /><br />and, get the right one for your motor. not the 70hp. just cause it mayTECHNICALLY fit, it may not be right for your application

 

[markhorton1979]

Re: LOWER UNIT 50HP & 70HP SWAP

Originally posted by myoutboards:<br /> why not repair the one you have? sounds like your dealer is trying to sell you parts!<br /><br />and, get the right one for your motor. not the 70hp. just cause it mayTECHNICALLY fit, it may not be right for your application

How do I go about repairing the one I have?