Not enough holeshot power - 2003 Bayliner 185 4.3L Mercruiser 14 x 23p

[Memorom]

Hi there,

I just got my new boat this weekend and was shocked to have trouble pulling my wife up on a single ski. She is only 5' 7" and not at all heavy and she is an experienced skier. My tachometer is broken (new one on order!) but the engine will easily plane after a few seconds, maybe 4, and easily gets to 50 MPH - only kept there for a few seconds since I don't know the RPM, but it does not struggle at all to get there. The engine is "running on" for quite a while when it is warm/hot after running for a while, but does not run on when it gets a chance to cool down.

1) Performance issue you are trying to correct - poor whole shot performance, can't pull up adult skier on single ski (deep water)
2) Current prop manufacturer, model, aluminum or stainless as a minimum - brand new aluminum, standard 3 blade prop (seller replaced it just before selling, I'm not sure if he ever used it for skiing)
3) Current prop diameter and pitch (required) - 14 x 23p
4) Wide open throttle RPM and speed with an average load (very helpful) - sorry, don't have it, but not struggling, have seen it get to 50 MPH (2 adults and 2 kids), so I would probably say around 4800 RPM
5) Engine/drive make, model, year, and HP - 2003 Mercruiser 4.3L 190HP, Alpha One leg, 1:81 gear ratio
6) Boat make model, year, length and weight - 2003 Bayliner Capri 185, 18.5', around ~2100 lbs

Any help or advise would be greatly appreciated. There is a local guy here with a Quicksilver Merc SS 4 blade prop at 14.5 x 21p that is in perfect shape and he's asking $300 CDN for it. He bought it for his 3.0L 175 Bayliner and ended up selling his boat. Will it fix my hole shot problems and get us out of the water? I don't want to drop another $300 and find it doesn't solve my problem.

Thanks in advance for any responses,
Steve

 

[steelespike]

A 23" prop is too much for water sports Assuming your speed is accurate (gps speed is best)assuming 13% slip a 23" at 50 calculates to about 4776 rpm.
The same prop in a 21"4 blade should help your hole shot.will cost some top end.Its also possible that, if available, a 23" Spitfire 4 blade may help hole shot without sacrificing top end.
The ss 21" should also solve your problem and may temper the top end loss.
But a 21" al prop could do well for less money.
I've seen two independent Spitfire tests that were impressive.
Keep in mind that prop results are not carved in stone and on rare occasions can be disappointing.
What ever prop you try Most people resell a prop that doesn't perform as expected.

 

[midcarolina]

Any idea if the po was into watersports? if so the reason the prop is new is he may have removed the expensive prop and installed the aluminum............ many people use different props depending on what they are going out to do......water sports or speeding around.

Once you get the tach squared away you will be in a much better situation to determine the best prop for water sports.

When we go out to play in the water I install my 18 pitch 4 blade...........that works very well, but if you make a big reduction in pitch to really increase hole shot a functioning tach is mandatory to keep revs under max......... with the 18' I cannot run anywhere near wide open throttle, but it's no big deal cause it's not needed when out wakeboarding/kneeboarding.

 

[SkiDad]

if your engine was really struggling to pull her I'd put on a 19p and just not go over 40 mph until my tach was fixed. or possibly the Alpha 4 in 20p. Either would be a good prop to have anyhow if you take a lot of adults with you at some point. Thats just me. A smaller diameter will help the prop spin up faster - say a 14" diameter vs 14.5

 

[Memorom]

Thanks for the responses. It definitely sounds like pitch from what I am reading on other posts as well. Since the SS is available and seems like the right specs, should I go for it for the $300? It's pretty rare to find a good used one for about half price of a new one. I am sure I can always sell it if I want to later and pick up a cheaper aluminum. Sounds like a 21p with the 4 blade will improve the hole shot while still maintaining top end. Any reason not to other than I can probably save about $100-150 if I just get a lower pitch 4 blade aluminum?

 

[Starcraft5834]

aluminum will perform well also, it also will bend easier,, which is nice should you hit something,, the SS is much harder, same hit may damage your lower unit axle system, while same hit to alumimum likely not..... my 2 cents............. 4 blade is the ticket

 

[steelespike]

The hub on the ss prop should protect the drive train.
If you boat where your likely to strike something hard(rock)
The ss costs more to repair.If you boat where your likely to strike sand or mud the ss will hold up better.
The ss will probably out perform an al prop.
Nothing wrong about buying the ss prop.

 

[QC]

I don't think I'd spend money on SS until I got the tach fixed and verified as accurate. My.02. Agree on previous pitch statements.

 

[Memorom]

I talked to a few marine shops here locally and they all say go for the SS 4 blade 21p. It is only one step down from the prop that is on it and if the RPM's are fine with it (will verify with new tach) then the SS with 4 blade and pitch correction should get anyone I want out of the water. Everything I will be doing will be lake from dock to dock and will be extra careful with the SS. For $300 they say it is a steal if it comes in pristine shape and hub kit. Going to pick it up tonight...can always sell it again if I have to if it doesn't work out with RPM. It's rare to find a good used one and I don't want to miss my chance at this price.

Also, I am still in the money spending mode...I just bought the boat on Friday and been spending money on jackets, tubes and gear all week. So if I don't do it now, reality will catch up with me and I'll never have a SS. ;-)

Thanks for all the help guys...I will post my results when I can. It's supposed to rain all weekend, but a holiday Monday so I am hoping to be out in the next week.

One last question, anything to look out for or any advise or tips and tricks for swapping the prop? I've never replaced one myself. I don't need to bring it to a shop do I? I know, youtube is my friend, but just looking for some expert tips if any are required.

Steve

 

[QC]

Changing a prop is very easy. Just grease the shaft and it will continue to be easy Make sure you put the pieces of the hub kit back in same order. It can seem pretty flakey, but once the nut is on it all tightens up correctly.

 

[Starcraft5834]

Assuming the ss prop fits your drive...easy install...

 

[jestor68]

The motor "running on" for quite a while is the serious issue here.

You better have the timing checked and/or use a better quality gas before you ruin the motor(rod and main bearings).

The "standard" prop that came on the boat was a 14.25 X 21 pitch. Testing indicated 46 mph @ 4500 rpm with a test weight of a little over 3000 lbs.

A 21 pitch 4 blade wouldn't improve your pulling power; especially since it's a SS prop and the "standard" prop was aluminum.

A 19 pitch would be appropriate for pulling.

What brand/type of SS 4 blade are you considering? They're all over the place in terms of performance.

 

[White90GT]

I didn't see anyone suggesting a tune up on the engine. Granted a 23 prop is probably too much for skiing anyways, but if the plugs and wires are old and the distributor cap/rotor aren't clean, there is a good bit of power sitting there. I hadn't done plugs/wires on my boat with 4.3l Vortec setup for at least a few years and don't recall every cleaning the contacts in the distributor cap. Well, I did that last year and wow what a difference! I was literally jumping waves with the boat by working the throttle after the tune up. Felt like a jet ski it was jumping up on plane so quick.

 

[QC]

I think his suggestion that he was seeing over 50 MPH gave us some confidence in the engine's condition, but you make a good point. No propeller decisions can be made without confidence in:

1) All of the relevant data: gear ratio, pitch, RPM, speed
2) Engine condition
3) typical load
4) trim use

 

[Memorom]

I bought the Mercury Offshore SS 21p 4 blade prop and went out this weekend. I am happy to report that I got my wife up each time and found a fairly considerable improvement up to plane! I am still a little disappointed with the starting power from the engine though...it seems like there is way too much lag from the throttle before the engine bursts to life. It seems to suck air at the beginning for the first 3-4 inches of throttle from when it is put in to gear...so I am having to roll forward a bit to get the RPM starting to build and then have to do a fairly slow roll up to wide open, then it gets up to plane in just a couple of seconds. But I can't "punch it" as I'd like to as it just sucks air and bogs down for the first second or so.

But this is extremely hard on the skier as it drags them a bit at idle in gear and then bringing the throttle forward a bit drags them a bit more until I can roll it forward. This is my first boat and I am a rookie at this, but it just seems like there is way to much play before the power really kicks in. Could it be that I need an adjustment on the throttle cable? I am used to a more instant feedback from the engine like from a car or motor cycle where the power is almost instantaneous. Is this just normal from a boat. For 190HP I thought I would feel it right away.

Additional comments or suggestions are welcome.

Alsofor the run-on issue, it is still happening a bit, but will be adjusting my idle down a bit based on suggestions from Mercury's TSB on the subject. If you are interested, here is the article...

http://www.marinemechanic.com/merc/distributors/mercurymarine/sterndrive/run-on-dieseling.PDF

Thanks for the help guys!

Steve

 

[midcarolina]

Sounds like you may have some carb issues..........If the motor is bogging with a fast wick of the throttle something aint right, you should not have to roll on the gas to avoid a bog condition.

Also sent you a private message.

 

[Memorom]

Thanks midcarolina...thanks for confirming my suspicions. I will discuss with the Marine Dealership here and decide how best to tune up the carb. I don't see a private message, how do I see that in my Account? There is nothing in my Inbox.

Steve

 

[midcarolina]

I think the pm is still a little screwed....... sometimes it works and other times it don't I sent the message again, It is showing in my sent box so maybe you will get it this time.......
You should see a messages icon in the upper right corner of page, when you get a message a little red box will show up in the corner of the message box

 

[DaveG55]

Since it's a new boat to you you should do a full tune up including plugs, wires, cap, rotor, oil change, new filters, etc. I'd also run some carb cleaner through to see if that helps. If nothing else helps you may have to consider a carb clean / rebuild paying attention to the accelerator pump.
Did the PO give you any history on the boat, like winterizing procedures he used or if it sat for a while?

 

[Memorom]

Hi Everyone,

Just a last quick update after this weekend. I finally got out with my new tach installed and had a full day of water-skiing with some bigger guys. First off, the RPM's with the new 4 blade, 21p prop are bang on. With 7 people in the boat I rolled it up to about 48 MPH and the RPM's were a nice steady 4700-4800 RPM Properly trimmed and on flat water with less people I think it will get over 50 MPH without any stress on the engine keeping the RPM's under 5K.

For the holeshot, I still feel like there should be more throttle acceleration from the first punch, but I was successful getting my wife up, her brother and a larger (6'+, 200 lbs+) friend up on a slalom, both feet in, from deep water with a couple of adults in the boat. And I even got up on my first try my first time on a single ski with both feet in in deep water.

So I think I am good. I need a tune up; change the oil, carb clean, distributor cap clean/replace, new fuel filter and new plugs and I think I will be golden. I'll ask the techs if I need a throttle cable adjustment etc. when I get it all tuned up and get it winterized. As it is my first boat, I am going to get the shop to do the work and then I should be humming next year. I hope to get out a bunch more times this year before it gets too cold but I think I can use it the way it is for this year.

Thanks for the help and comments!

Steve