The 21 & 23 are the same block construction and 38 CID. The 18's are smaller enginer and 35 CID.
The 21/23's have a much different carb (21/23 is dual bore, 18 single), air cleaner, and muffler package to accommodate the extra HP. Throughout the engine there are major differences in cylinder head, crank, block, etc.
I don't recall the compression spec being different.
Rated speed is all the same ... 3600.
In use, the 18's and 21/23s are different machines ... with the marginal HP for the 23HP mostly noticed when fully loaded up on a hydravac, snow thrower w/PwrStrg, etc.
I too was a little put off initially in Ingersoll's price points for these, until coming to grips with the 21/23's being the larger engine. You can compare almost any Vanguard equipped prices points and they step up at this level.
Brian
The 21/23's have a much different carb (21/23 is dual bore, 18 single), air cleaner, and muffler package to accommodate the extra HP. Throughout the engine there are major differences in cylinder head, crank, block, etc.
I don't recall the compression spec being different.
Rated speed is all the same ... 3600.
In use, the 18's and 21/23s are different machines ... with the marginal HP for the 23HP mostly noticed when fully loaded up on a hydravac, snow thrower w/PwrStrg, etc.
I too was a little put off initially in Ingersoll's price points for these, until coming to grips with the 21/23's being the larger engine. You can compare almost any Vanguard equipped prices points and they step up at this level.
Brian
