I had always been under the impressing that there was more to it than just a shop press, as ubiquitous as such presses are. Or is that a "if you had to ask, you're not supposed to know" smoke and mirrors show? Perhaps, a "you can but you'll ruin it" situation, which would put me in luck if all I...
Here's an atypical prop question: I have four aluminum props sitting around with rubber hubs. One has a spun hub (pressed Mercruiser), one has hub starting to dry rot (Michigan Wheel that appears to be pressed), and two have substantial damage (both are pressed Mercruisers, one has a rotted hub...
I have. I have an 18 pitch 4 bladed prop that hits middle of WOT range under load, while I have a 19 pitch 3 bladed prop that hits top of WOT range under load. The 19 runs a bit faster. But the 4 blade has more lift and doesn't respond to trimming... and also has a buttload of rake to the point...
Technically, it can be if comparing props of different types (material, blade count, rake, diameter, etc.), although the "is is a correct prop" determination is a factor of WOT RPM and what the engine's spec calls for.
But the relation to ground (GPS) speed may be close enough depending on the activity? Example being pulling a tube/skier on a lake or river... if the current is enough that the error introduced becomes significant, then (at least where I boat and pull such things) it's probably not a good...
Here's a video of one of the full throttle tests. In this one I topped out at 46mph. An earlier run (not videoed) hit 47 briefly, but that's splitting hairs. Turning about 4000 RPM.
I GPS'd my gauges when I redid them as part of a larger overhaul (pitot tube setup was destroyed and useless). But while I mostly used Faria gauges like you chose (literally the same models), I went with a "generic" cheapie LCD unit for the Speedometer as that also grants me heading (never use...
Results:
On the 21 pitch prop, I was able to hit a WOT of 3950-4000RPM, right near the middle of the range. Top speed was 45-47mph in the most favorable wind/current. Fuel economy was good too. Same results as the first time other than the RPM... maybe back then I did hit 3900 or so back then...
Going to give the 21 one more try tomorrow on the river (or so is the plan). Just my wife and I, running as light as we'd ever run. Less wind so hopefully I'll be able to WOT it more without getting wrecked.
Good point on the cam grind.
Did you mean 1980? My boat is a 1976. And one of the two 888 outdrives I've salvaged came from an early 80's boat (1982, if memory serves and the seller was accurate).
Piranha uses a composite core (Aluminum inner, reinforced plastic outer) and reinforced plastic...
Oh I know. I just like Piranha and the blades being a serviceable part that doubles as a mechanical fuse in the event of a strike. One of the lakes I frequent seems to have a lot of hidden prop busters.
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Apparently I had it in my head the upper end of the WOT range is a redline... no, the...
Yes. 4200 on the 19 with 4 people is likely too high if running lighter... so that'd make the 21 with two people at 3700 the lesser evil if running light?
My fear is overrevving and floating valves. Other than the intake the top end is stock.
