True this would be the most accurate way. I was just going from what the engine sounded like. If I can be at half throttle and have the boat around 5 knots and a bit better reverse I would be happy. I'll take a look around to see how available or how expensive a temp tach would be. I am a bit curious.
high thrust prop
- Thread starter katana750
- Start date
- Status
True this would be the most accurate way. I was just going from what the engine sounded like. If I can be at half throttle and have the boat around 5 knots and a bit better reverse I would be happy. I'll take a look around to see how available or how expensive a temp tach would be. I am a bit curious.
since you posted your speeds, here is what I believe mine are (going from memory).. maybe this well help?? Ive noted elevation as this makes a significant difference. Outboard is a 2010 Nissan 9.8 four stroke with the "mid altitude" jets.
High thrust four blade 5 pitch prop - WOT at about 5200 ft el = 6.25 knots
8.5 pitch 3 blade "swept back" prop - WOT at 5200 ft el = 6.17 knots
8.5 pitch 3 blade "swept back" prop - WOT at 600 ft el = 6.6 knots
My typical cruising speed "about half throttle" with 8.5 pitch 3 blade = 5.65 knots
I beleive my outboard wiring diagram shows a connector for some sort of RPM gauge but Ive never looked into it (no real problem I need solved..). But it would be somewhat interesting.
High thrust four blade 5 pitch prop - WOT at about 5200 ft el = 6.25 knots
8.5 pitch 3 blade "swept back" prop - WOT at 5200 ft el = 6.17 knots
8.5 pitch 3 blade "swept back" prop - WOT at 600 ft el = 6.6 knots
My typical cruising speed "about half throttle" with 8.5 pitch 3 blade = 5.65 knots
I beleive my outboard wiring diagram shows a connector for some sort of RPM gauge but Ive never looked into it (no real problem I need solved..). But it would be somewhat interesting.
Thanks that is a helpful referance point....I have been looking at some of your other posts and your the numbers do give me an idea what I should be aiming for. Rpm would be kind of nice to know, but I probably would never use the meter again. Still if it isn't too expensive......
These things are all over the place, and they're cheap ($14 with free shipping).* I have something like that, and it's pretty accurate compared to a contact type unit I also have, as checked against a couple of induction motors.** Certainly accurate enough to know if you're up in the design range or not.
http://www.ebay.com/itm/Digital-Las...ltDomain_0&hash=item58a018c5ed#ht_2806wt_1187
*No connection to this or any other auction or sale of this or things like this - it's just the first one I came upon when searching.
**AC induction motors will run just a few rpm less than synchronous speed unloaded, synchronous speed being 1800 and 3600 rpm for 4- and 2-pole motors (respectively) on 60Hz power.
Curiousty will get the better of me....I'm probably going to order one. I'll get one next time I order some more items from the internet. Or I fluke out and find free shipping to BC. In the mean time I ordered a 4 blade 7 pitch prop. I'll try it, just from what others said I probably can't go too far wrong.
Thanks
Thanks
I just looked at that little meter it looks perfect. I tried to look up how you would use it to measure rpms on the outboard. This might be a dumb question but what would you point it at. My first thought would be the fly wheel but that can't be right.
Never mind the fly wheel would be the answer
- Status