Perkins 4.236 Fuel Consumption

[lolder]

I had a 4 236 with a Paragon P 200 hydraulic transmission in a 30 000 lb
Morgan O. I. 41. At 1650 rpm it went 6.5 kts. on 1.1 gph. Prop I think was 20 x 24. WOT yielded 2500 rpm and almost 8 kts. These engines are bullet proof.

[Kettlewell]

2400 rpm? My 4.236 manual says the redline is 2250. I tend to cruise at 1200-1500 rpm, and very rarely up to 1700 rpm when trying to make a bridge opening or something. On my 38-foot motorsailor I get around 5.4 knots at 1200, 6 knots at 1500, and just over 7 knots at 1700. Burns about 1 gallon per hour at 1500.

[lolder]

There were several rpm ratings for the 4 236 depending on use. Mine was 2500 rpm at 85 hp as I recall
There may have been a time limit. 2250 was probably max continuous. It was a long time ago. 1800 was my max cruise at about 7 knots. After repowering my OI41 with the 4 236 I did a full throttle test and it went at least to 2250 and 8 kts. Lots of noise. 6.7 kts was the sweet spot for the OI41. The 4 236 was used a lot as an 1800 rpm generator and in British Taxis. Look up Perkins 4 236M