odd engine serial number

[Keith L]

The 154 that I'm working on seems to have an odd engine serial number.
I have an extra 154 enginethat is a little older that has a number that makes sense. The older engine has an R date code and a serial # of FCUBM xxxxxxxx.
The 154 that I am working on is an X date code with a 33xxx chassis serial number that puts it as a 1974. Sometime 1974 they started making the 185's.
Anyway, the engine serial number is 60CT2U300336X. The engine also has a series of large double dashes cast on the carb side of the block that I have never seen.
What do you think?

[gitractorman]

According to serial number records IH did not start making the 185 tractors until late in 1974. Matter of fact, only 315 of the 185s were made in 1974, serial numbers 37001 to 37315 were the ones built in 1974. Therefore, the engine that you have is most likely correct, and the X code is likely indicator of a late 1974 casting.

Here is something that may be interesting to check out, and may be the answer to the dash marks on the carb side of the engine. Sometime prior to production of the 185s, the engines were changed by addition of the Zenith carburetor, domed pistons (I think), and increasing the engine rpm, to get the engine horsepower up from 15hp (in the 154s) to 18-hp (in the 185s). Since yours is a late production 154, it is quite possible that it actually has the 18-hp engine. The dashes in the engine may have been indicators so that during production the correct pistons and carburetor were installed. This is clearly just a guess on my part, but it is not out of reason. IH is known throughout history to overlap production like this, using parts from previous years models on the next years model, etc.

Hope this helps,
Bill

[Keith L]

Thanks, Bill
That all makes sense but the serial number prefix still seems odd. Here is a picture of the double dashes