1976 Johnson 75 HP lower unit

[PAMeyer]

I just joined this forum and I really think it's great. I recently purchased this engine and have a few questions. First, it seems difficult to find this engine in the parts web sites. Many (including Iboats.com I believe)don't list the 3-cyl 75 HP engines between 74 and 77. Is there something unusual about this engine? Specifically, I need to replace the drive shaft thrust bearing and lower unit seals. Can someone suggest a source? Also, the Clymer manual references a shim gauge. Does anyone know the gauge dimension for this engine - I have access to precision measuring equipment but need the correct dimension. Finally, WOT is about 6000 RPM, is this too fast? Thanks for your help.

 

[Dhadley]

Re: 1976 Johnson 75 HP lower unit

Welcome!!<br /><br />The majority of the powerhead parts are the same as the 70 hp of the same year. Some 75's were 15" motors. Without your model number its hard to say what you have for sure.<br /><br />6000 is nothing for the 49 cid motors. Thats a good set up rpm.

 

[PAMeyer]

Re: 1976 Johnson 75 HP lower unit

Thanks for the quick reply. The model number is 75ELR76D and the serial number is J4551256. I looked again at the Iboats.com web site and I don't see a listing for the lower unit for this engine in 1976. The listings seem to start in 1978. Is the same lower unit used on other models? Also, for other years, I see mention of "large housings" and "small housings" on the lower unit. Which do I have? Should there be any identification numbers on the lower unit itself? Thanks.