OT: Boat and motor setup question

[BoneDigger]

I feel like my Yamaha isn't pushing my boat well enough (it's an older motor). Does anyone offer a boat/motor setup service that would take the boat on the water and make all necessary adjustments to make it run correctly, and also check the engine over completely to see if it is "giving it all it's got?" I'm talking checking the prop pitch, motor height, throttle adjustments, etc.?

I have a 20 ft Nitro (1989) with a 220 Yamaha (1984) and it only pushes the boat to 53 mph. I would think that 220 would get it up to at least 70. Anyone know a service person that offers a setup service?

Todd

[BrianL]

53mph over the water isn't fast enough?????

[Dru]

Bonedigger,

What RPM's are you running at 53 mph? What is your water pressure at that speed?
Does the boat have a jackplate?

[Ouch]

Call and talk to Larry at East Texas on 155 South. He's one of those that you either love him or hate him, but he's honest.

I would talk to him and just ask. He'll talk to you a bit, maybe even talk you out of bringing it in. He did that for me on my last boat. Ended up making the adjustments myself (by his advice), saved me some cash.

[BoneDigger]

Brian, yes that's fast enough, but it sucks that the boat isn't living up to its potential.

Dru, Turning around 5200 at WOT. I do not have a water pressure gauge (yeah, I know, GET ONE!). Yes the boat has a jack plate. I have it set at about 4 inches below the stepped transom as per recommendations from others. The hole shot is good, but the speed isn't there.

I am running a 21 pitch three blade prop.

Todd

[BoneDigger]

Thanks Ouch, I have had him work on boats before. I'm really tired of tinkering with this and would like to pay someone to figure it out.

My guess is that the hotfoot may not be adjusted correctly, but that's a guess.

I also realize its a HEAVY boat.

Todd

[Dru]

4 inches below pad is a little low IMO. You would be safe to raise it up an inch but do so in 1/4 inch intervals. As long as the water pressure stays good you can go up until you hit 5800-6000 rpms

You might also try a 23 pitch prop.

How far can you trim it up before it starts getting squirly?

try looking for that motor/boat combo at

http://bbcboards.zeroforum.com/zeroforum?id=11

[BOSSMAN]

What prop do you run on the engine maybe just a pitch problem. I had a skeeter I bought new but it had the wrong prop from the factory the dealer changed it and I gained 10 mph just a thought .

[BoneDigger]

I went up another couple of inches a while back and was getting a lot of slippage, so I went back down.

I can't trim it up much before it starts porpoising.

I talked to Steve's Prop Shop on Fork and he said a higher pitch would still probably only give me another 1-2 mph top end.

Todd

[Dru]

I went up another couple of inches a while back and was getting a lot of slippage, so I went back down.

I can't trim it up much before it starts porpoising.


Todd

It may be the prop then. How much weight (tackle etc.) do you have up front?

5200 rpms is lite. You might have a compression check done on the motor.

[Mike]

You need to get the RPM's up to at least 5600, IMO. That is an older rig and you might not want to start tinkering with it at this point, just be happy with the performance.

I spent a lot of time dialing in my rigs with props and positions, more or less spending a day or two at the ramp loading and unloading after making some runs.

I would make sure the 21P is really a 21P prop, due to age I would think some work has been done to it and it might be more. I would not go smaller unless you went to a 4 blade. You are playing with hole shot and handling vs speed and you will have to make a decision on what you want and go that direction.

I will toss this out there, from just reading this, you might need to start out raising the motor if the top of your gearcase is 4" lower than the pad. The best case for speed is one blade in the water, one entering and one exiting, or pretty close to that picture.

I would move it up a bit and see what happens, if the RPM's go up and all stays well like the hole shot, staying on pad at slow speeds and such then leave it there,

To me, it is a heavy rig with a heavy motor and I would leave it as is if it gets you from point A to point B at 53 mph.

[PEC]

The early model Nitros were fast hulls. The motor sound weak, with a 21 on that motor is should be hitting the rev limiter even on a 20' boat. I would check compression on all cylinders and make sure they are all getting fuel and fire.