Observations on my V20

Yesterday I decided to take my V20 out of the brine and to a fresh water river to blow some salt out of it. Well I had pumped my 60 gallon tank out due to the fact it has some water in it. I had added some water evoperator to the tank, so I just took a 12 gallon and 6 gallon portable tank. I filled both up. I put some Ring Free in each tank, a some mix of outboard oil, and about half a can of Seafoam. Started it up and I was on my way. I have a 1990 Yamaha outboard. I was running off the six gallon tank w/ an in-line filter with a sight glass by SeaChoice. I am spinning a 14 1/2 x 17 pitch ss prop. At 5000 RPMs (WOT) she was up to 40 mph and trimmed out all the way. She preformed great. Well, I am after a bit more speed and increased RPMs. I know the prop basics. But I am sure you guys have a tried and true method to get more speed out of these motors and boats. The boat is excellent on gas. Out of that 6 gallon tank at full throttle for 75% of the time I went 17 1/4 miles. ABout 3.8 MPG. Not real bad I thought. I check the compression yesterday on the warm block and she read, 110lbs to120lbs all the way. I am using regular BH8HS-10 NGK plugs what the motor calls for, any suggestions on better plugs? Give me some feedback on these situations guys..Thanks....Dirk and Al

[reelapeelin]

Dirk, mines only gettin' 42 @ WOT...assumin' yours is 150hp you're in the right neighborhood...I'm spinnin' a 15 1/4'' x17 prop, so just a little more dia., but honestly, if you're gettin' all the mfgr's recommended max rpm's, you're about topped-out... 8) ...

[Airslot]

If she's running good...well if it ain't broke you know what to do...leave it alone. I'd think she'd pull a few more rpm's with a 17p prop, but all your other numbers look great. Enjoy...

Airslot

[Pipe_Dream]

Originally Posted by Airslot

If she's running good...well if it ain't broke you know what to do...leave it alone.

Airslot

Ditto that. What's your hp?

Thanks guys, I thought so as well. Yes she is a 150 by the way, and I am happy with the mileage shes getting. Got her on the trailer now and planning to do some much needed repairs to the boat itself. Passenger side window has to be refastened for one. Again, thanks for all the input....Dirk

[Blue_Runner]

Good numbers and by the way - that's exactly what I'm needing to do :D

[macojoe]

I think you are fine!! Don't change a thing!

passenger side window needs to be refastened? wher you at? i just follow you up and down the river till that thing blows off. finders keepers,lol. stink, you still got those starboard winders?

you know, i got an idea for how to hook NOS up to an outboard. we could port and polish the exhaust. upgrade the carbs... what kinda reeds you runnin? how much money you got? if it aint broke dont fix it?... you guys are just old,lol

Here are a few things that you can do w/o monkeying with the motor.

1. Switch Props to a 17 pitch Mercury Mirage Plus or Enertia.

2. Raise the motor up a few holes (get the cavitation plate 2" or 3" above the bottom of the hull)

a hydraulic jack plate works even better.

3. Remove any extra weight

4. Trim Tabs

p.s. - that motor likes to be propped at 5500rpm.

when trimming the motor at WOT . . . Don't forget to raise the motor up until it starts to lose it bite and then lower it back down little by little until you get a good bite.

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Engine mods . . . if you want to kill fuel economy.

Look up posts from Ray Neudecker on screamandfly.com (also old posts from boatsetup.com)
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There are many bolt on engine mods for 2.6L Yamaha's . . .

You can make that motor put out well over 200hp if you can snag parts off an old 225 excel or 220 special.

Swap to a horizontal front half (crankcase) and intake
Swap carbs 220 special or 225 excel.
Change the Tuner and exhaust divider, heads.
remove the oil injection.
Set timing.