Question about engine rpm's

[Techna22v]

New to me boat (03 22v) and I'm concerned about the rpm of the boat.

What rpm range should I be at while going 22-23mph and I was always having to adjust the throttle to keep that speed. I feel I was adjusting 5 deg or more on the throttle to get it to stay there.

22v with acme 537, mercruiser 350, 500lbs lead, no water ballast and full of people. 6 adults and 5 kids.

really stupid question.... Were does the ice chest drain? I had a dry bilge when we pulled the boat out and I know we had about 30lbs of ice in that thing. I keep hearing about the low point in the middle, if that's were it went how do I get the water out?

[chpthril]

O3 V drive with a 4 blade and I have to ask, what ratio v-drive? Is it blue or black

[Techna22v]

O3 V drive with a 4 blade and I have to ask, what ratio v-drive? Is it blue or black

Acme 537 4blade and from what I remember its the blue one.

I really need to start my list of parts and model numbers. I should have Friday off, so that will be the next time I get back to check for sure.

[TigeFamily]

rpm will vary based on engine and prop configuration, maybe Chp will be able to answer that better since he had similar boat...
All older boats I ever owned you had to keep adjusting throttle to keep it at specific speed unless it has some sort of GPS speed control.

[Techna22v]

I was able to get by the shop today and can confirm that is is a "BLUE" v-drive

[ski_antique]

I was able to get by the shop today and can confirm that is is a "BLUE" v-drive

it sounds like you need less pitch on your prop. PP will surge when you are pushing more than ideal configuration of propeller/weight. A few hundred more rpms makes a big difference...or a few hundred less pounds in the boat.


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[Thegerman618]

2 potentials
1. Is your cruise control on? If so turn it off.
2. Check the key on the prop to make sure your not slipping the prop on the shaft.

Yes the cooler drains to the bilge, the low point is right in front of the prop shaft. Leave the plug out and park on a steep hill. It will drain.

[Techna22v]

it sounds like you need less pitch on your prop. PP will surge when you are pushing more than ideal configuration of propeller/weight. A few hundred more rpms makes a big difference...or a few hundred less pounds in the boat.

Stock prop from the factory, no ballast, no PP

It may just be me, having come from DD, but the boat feels sluggish and just doesn't take off like I'm use to. I feel the RPM's are on the high side too.

[Thegerman618]

I can promise you with a stock prop, lead, and 6 people/kids no VDrive will launch like a DD. The 22ve is just a heavier boat altogether and you may not need ballast. With 6 people and kids your on the limit of the stock prop any how. Call acme and get a heavy ballast rated prop. Likely fix your issues and may even give you the bottom end pick up your looking for.

[chpthril]

but the boat feels sluggish and just doesn't take off like I'm use to. I feel the RPM's are on the high side too.

These 2 complaints in one sentence and boat is fitted with a 537?????????? Something is not adding up. Very little ballast or moderate crew numbers in a 22V and the 537 still has some @$$ to it. However, with its 16" pitch, high RPMs, I dont see it. Id look for a slipping trans or a damaged prop, or engine issue.

[Bakes5]

"537","sluggish" and "doesn't take off" makes sense. RPMs on the high side is a little subjective though. Really we need your engine, WOT speed and RPM before we can say anything. My 98 2200v was great at sea level with a reasonable crew. Go up to altitude, add people and weight and all of a sudden it was a total dog. Could not believe it was even the same boat. Re-propped it and it was great again although I lost a bunch at the top end.

[Techna22v]

The prop on the boat is "brand" new. The original owner of the boat bought a spare 537 prop with the boat. The one on the boat was nicked by the trailer, so I took that one off and replaced with the spare one which was never used.

I had the tranny, vdrive and motor gone through by a local shop, Flushed and all new fluids, checked plugs, replaced belts and impellers. Next time we are out I can do a WOT test, and I'll bring my GPS out to verify speed, and speed vs RPM table.

Curious question what prop would you go to if you wanted more down low power, I don't need the top end speed. I was staring at the ACME 1433

[chpthril]

The 1433 is a good upgrade to the 537, however, due to its lower pitch, it will raise RPMs, which is one of your concerns.

[Techna22v]

The 1433 is a good upgrade to the 537, however, due to its lower pitch, it will raise RPMs, which is one of your concerns.

Please don't get me wrong I don't feel the RPM's put the motor in a dangerous level. It's just much higher then I'm use to and want to make sure know all the baseline numbers.

Example:

old boat was a 1984 Ski Nautique 2001, 351 motor with a ACME 542 (spare OJ original) I would maintain 22-23mph at 2700-2800rpm with very little throttle adjusment
New one is a 2003 Tige 22v with mercruiser 350, ACME 537, 22-23mph at 3500-3800rpm with lots of adjustments to the throttle and it would not hold speed well I would drift 21-25 sometimes before I made an adjustment, thinking that maybe the boarder was causing the swings.

I do know this might just be normal for the boat and I'm just looking for normal operating info.

[chpthril]

I understand. the lower pitch prop will likely add 100-200 more RPM, depending on load.