Jacobsen Model ID?

[Rake60]

I picked this Jacobsen engine up yesterday.
Can anyone tell me what Model it is?
It has a Tillotson MT3A carb on it.

[Andrew Mackey]

Looks like an early '50s 321 style engine - rated @21/4 HP. Your particular engine was only made a couple of years, and then the starter was re-designed. This was due to the fact that B&S was planning to sue Jacobsen for patent infringement . The ball and sprag starter on your engine was too close in design to the one made by B&S , and Jacobsen did not want to pay the royalties, so it was scrapped. They are a nice display engine.
Andrew

[Bill Geyer]

Hello All,

Look at the as base of the cylinder, if it bolts to the crankcase, it's a J-100 or J-125. I'm pretty sure a J-100 because of the older sheet metal. Older ones have B-10 carb with built on adaptor, later the MT with separate adaptor.

Hope this helps
Bill

[Rake60]

OK
Well this one has a removable cylinder.

And an MT3A carb with a seperate adaptor.

I havn't pulled the cylinder off yet to clean it out, so I don't know
what the bore size is. It starts and runs, but not great.

Rick

[Byron Roberts]

Rick ::You might not have to tear it apart..The manual we found for the J100 sez clean carbon out of manifold periodically....If it is a J 100..I can scan some pages if you want...HTH..Byron.. At the risk of this getting deleated..I'l see you at LMC..

[Rake60]

Not tear it apart???
I have to tear it apart!
When I was a kid at I had all my Christmas toys broken by
New Years, but I knew exactly how they worked!!!

Rick

[Bill Geyer]

Hey Rake,

I was gonna tell you no! don't tear it down, I'll tell you the bore.
But in the interest of all of the broken Christmas toys, especially the cute little 32 Ford with the visible clear plastic engine that I drilled a hole in and filled with oil. Go ahead tear it apart

Bill