Re: How much to trim to make 'test prop'?
Remember anything about how much of the diameter you removed? (1/2, 1/4?).<br /><br />OMC uses the same 10" x 2" test wheel, 382861 (probably old number), for 55-65 triples & 85/100 V4s. Also, the 115/125/135 wheel is only a bit bigger (11-1/4 x 2-3/16), and the 50 twin wheel is a bit smaller (9-7/8 x 2). Since the LU gear ratios are different, it works out (2/1, 2.6something/1, and 2.8something/1). The 85s and 100s are supposed to turn 4800. I have only tested one 85 and it did turn 4800 (not sure it was completely healthy). I've tested a couple mid-70s 115s on the 10x2 wheel, and they both turned around 5400 (making a lot more noise than the 85). <br /><br />By the way, the numbers for the 1960/70s 55/60/65 triples are 4600/4800/5200 - so the early 55/60 triples are definitely not as highly-tuned as the 65hp+.<br /><br />One reason I'm after this is that I just noticed the 1986+ 88/90s I work on have 1-3/16 carbs. The 115 (early and late) have 1-5/16 carbs. That's a huge difference in flow area. I'd always bought the story that at the 1986 horsepower re-rate, the old 115 became the 88/90, and the old 140 became the 115. I'll run a healthy 88SPL on the wheel, and see how it compares to the old 115s.
