Re: Difference Between 135 and 140 Johnson?
The last year for a 135 was 1976. In 77 it became 140 hp. There are two major differences between these engines when accounting for hp: The 140 (and some 115's) utilizes rubber intake filler blocks inside the intake manifold. Part number: 322684. Also, the 140 exhaust chest has a machined cut taken out which differentiates it from the 135 powerhead. See picture. This is a 135 block which has had a machined cut taken at the bottom of the exhaust chest to make it similar to the 140 factory cut. In addition, the 135's had a single thermostat (vernatherm,) the 140's have the redesigned thermostat housing with two stats. When this stat housing change took place, the mounting face of the powerhead was changed and so was the midsection exhaust adapter. So a 135 will not fit on a 140 leg. By 1978 all V4's had a different shift linkage mechanism under the bottom carb and dual power packs. By 1979 all V4 powerheads used the same block size, 99.6 cubic inches. The 77 140 was a truly unique engine, in that it is the only one with an exhaust tuning megaphone in the midsection, like the V6 engines. The carbs are both probably 1 5/16" throats, but the 82 has no choke butterflys-it relies on the newer fuel primer system for cold starting.
