Do all Johnson outboards made after '59 definately have t-stats?

[joaklay]

Someone mentioned that in my other thread but I'd like to be 100% sure before buying another, newer model outboard manual attempting to know what HP motor I now have. For example, if it's a newer (late 60s, early 70s) 20 or 25HP powerhead, then it'd have to have a t-stat right? Mine does not, nor ever did have a t-stat so it then can't be later than '58 if that's true making it an 18HP.

 

[Chinewalker]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hi Joakley,<br /> For the most part, all OMC motors over 5hp, 1959 onwards have t-stats. 1958 was the last year for the 18hp to NOT have a thermostat - there's not bulge on the cylinder head the extends above the motor block.<br />- Scott

 

[joaklay]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hi Chinewalker,<br /> Well, I do believe you on that but when you say "for the most part", does that mean that perhaps there are exceptions to that rule?<br /> I'd have to think that they probably added t-stats to improve warm up time and thus get a better fuel mixture sooner as they do with cars (better emisions, drivability) and I wouldn't think that once the idea was in-use, they'd have exceptions for not using them in later years.

 

[Chinewalker]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hi Joakley,<br /> For the 22-cube series, of which your motor is a part of, 1959 was the first year for t-stats and all those built afterwards had them. I can't think of any 5hp or above motors that didn't have t-stats after 1959. The only motors without were the little kickers - the 1.5-4.5hp models.<br />- Scott

 

[joaklay]

Re: Do all Johnson outboards made after '59 definately have t-stats?

OK, Thanks

 

[Paul Moir]

Re: Do all Johnson outboards made after '59 definately have t-stats?

The '61 to '63 28hp (35.7 CID) engines had no thermostats. They were a 'value priced' model, and I think were mechanically similiar as the '50s 25hp models...

 

[joaklay]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hmmmm, now THAT's interesting. The outboards that I'm really wondering about (as for having/not having t-stats) would be the late 60s-early 70s 20 and 25HP models in particular. Might anyone here reading this have one or have experience with these to know 100% sure?<br /> The reason I need to know is that I'm still trying to identify the powerhead on my "'57 18 HP Johnson" that the guy I bought it from claimed to have replaced it with a newer 20 or 25HP powerhead yet I'm highly doubting that. I could ask the guy via e-mail for more details but I also don't want to accuse him of lying either and he's been honest and decent to me so far.<br /> Here's the thread that I originally posted on that IF anyone's at all interested in<br /> http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=28;t=017527 <br /><br /> I still have the comparison photos that the seller sent me comparing a '61 18HP and a '72 25HP side by side (as I asked him many times about this issue), they do look the same and BOTH obviously have t-stats too. You'ld think that he would have realized that the powerhead on MY 18HP doesn't have a t-stat?

 

[Chinewalker]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hi Joakley,<br /> ALL Johnrude 22-cubic inch blocks (18, 20, 25hp) from 1959 onwards had provisions for thermostats. If your block and head do not have provisions for a thermostat, then it is either a 1957 or 1958 block. Are there any numbers on the motor block, perhaps on a nickel sized freeze plug?<br />- Scott

 

[joaklay]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Yep, posted in the other thread too. The # on its freeze plug is 1722161. <br />There's also a # on the intake manifold, 203907<br /><br /> It has no provisions whatsoever for a t-stat.

 

[BillP]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Those numbers don't show in my manual...<br /><br />1960-1964 25hp & 28hp omc exploded diagrams and cooling system descriptions give no indication of tstats.<br /><br />1960-1968 15hp,18hp & 20hp show and describe tstats.

 

[joaklay]

Re: Do all Johnson outboards made after '59 definately have t-stats?

I've found a couple other pics of '57 18 HP Johnson motors and although they look similar, they don't seem to have the same fuel pump location (r side of cyl head on mine) and the flywheels don't have teeth for a starter. Mine has teeth for a starter BUT I suppose that part could have easily been swapped too?<br /> It's still somewhat of a mystery as to what powerhead mine has, so far.

 

[Chinewalker]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hi Joakley,<br /> Your block is, definitively, a 1958 Johnson 18hp block. A fuel pump is a very easy add-on, as a fuel pump ready intake transfer port cover will bolt right on. Electric starting was offered in 1958, so the ring-gear flywheel is not unusual.<br /> Therefore, your motor is an 18hp, plain and simple. It cannot easily be made into a 20 or 25hp, as those blocks were different - porting, intake, etc...<br />- Scott

 

[joaklay]

Re: Do all Johnson outboards made after '59 definately have t-stats?

Hi Chinewalker,<br /> Makes sense to me and after all this, I do believe that you're right. Still not sure why the seller made up the story however and I'm not sure if I should bother confronting him with it now.