1968 Johnson 100HP - Tips?

[gotgill]

Good evening. I am in the process of rebuilding a center console and found an ad for a 68 Johnson outboard- 100hp dirt cheap. I made arrangements to have a look at it tomorrow afternoon. Anything particular I should be looking for in a motor this old? (Major issues of course- im sure there is a lot to consider). The seller will test the compression for me while I am there. He also stated that he had it running a month ago but the ignition system needs to be replaced. A friend tells me that older johnsons came in high comp and low comp models. Is there a way to tell this easily?

Thanks in advance!

 

[DHPMARINE]

Re: 1968 Johnson 100HP - Tips?

Compression will be a moot point when you start pricing ignition parts.Don't buy it.

DHP

 

[Willyclay]

Re: 1968 Johnson 100HP - Tips?

I have the same motor(V4TL-14B) and it currently is not running because the engine wiring harness has deteriorated badly. Joe Reeves of this forum told me that OMC changed suppliers of wire products that year and had very bad results. I am faced with the option of replacing the harness or rewiring it myself and have not priced any other components. Good luck. Keep us posted on what you decide and how it goes if you buy this motor.

 

[gotgill]

Re: 1968 Johnson 100HP - Tips?

Thanks for the speedy responses and the advice! From my phone conversation with the seller- it seems this motor has the same issue Willyclay. Seller is also a mechanic so he says he would go over everything with me so we shall see. As it stands- he wants 100 bucks for the motor, a 19 ft westwind, and the trailer. Trailer alone is worth more than that if the motor is toast. He just needs the old boat off the property as they are selling their farm. Willyclay- any idea what your compression is at? Would be nice to base off a similar engine if the guy is willing to do it for me....

Thanks again all!!!

 

[Willyclay]

Re: 1968 Johnson 100HP - Tips?

Last time I checked compression(several years ago), had 100-115. My motor is in excellent condition except for the bad wiring harness. I may also have bad electrical components now because of all the shorts and just will not know until I can do a complete troubleshoot. That will not happen until I fix the wiring harness. First things first. Good luck with yours.

 

[gotgill]

Re: 1968 Johnson 100HP - Tips?

Thanks again for your time. I appreciate the help. In case you hadn't seen- I found engine diagrams with the instrument and cable groups here for free:
http://www.evinrude.com/en-US/Accessories/Literature/Engine.Diagrams.htm?popup=true

Troubleshooting guide (also free):
http://rapair.com/images/Downloads/Troubleshooting Guide 2006.pdf

Owners and service manuals (fee):
http://www.kencook.com/evinrudejohnsonmanuals/index.cfm?fuseaction=models.main&year=1968&ID=56170

 

[Willyclay]

Re: 1968 Johnson 100HP - Tips?

I apologize for not offering you BRP and Ken Cook sites since I was aware of them. Did not have RAPAIR. Thanks

 

[tashasdaddy]

Re: 1968 Johnson 100HP - Tips?

here's another good link, just go thru the pages to find your engine.

http://www.boatpartstore.com/page30.asp

and we can't forget Joe Reeves


http://forums.iboats.com/bbBoard.cgi?a=viewthread;fid=36;gtid=1278471

 

[gotgill]

Re: 1968 Johnson 100HP - Tips?

Thanks again for all the good advice- being less than a novice at this- it's nice to have some resources instead of going in blind. I plan on learning a lot from these refits- I can't thank all of you enough!

 

[Willyclay]

Re: 1968 Johnson 100HP - Tips?

I failed to address your basic question in your first post which is this motor low or high compression. I believe it is HIGH because the same motor came in two flavors, 90hp and 100hp. How much higher is another question. They both had the same displacement, carburetors, etc.

If you decide to buy the boat, motor and trailer because of the low price but do not want to fool with the motor, let me know. I could use a parts motor. Just found out yesterday from my local dealer, the engine electrical harness I need in no longer available from BRP!

 

[jimmbo]

Re: 1968 Johnson 100HP - Tips?

Try this link
http://www.ultimate.com/omc-boats/gallery/lee.shuster/68_100hp_V4.jpg

BTW. there was a difference in the compression betweeen the 100hp and the 90hp. It was one half a compression point more. ie) 6:1 vs. 5.5:1. That wasn't the only difference, porting was different. Also they weren't availible together, 90hp 1964-65, 100hp 1966-68