Boat running sluggish

[rktktpaul]

As stataed below, 4.3l V-6, Alpha 1 Gen 2 outdrive. I've run the boat the past 2 seasons with the 23 pitch prop the boat came with. With that setup, I have run about 45MPH (GPS) @ 4400RPM WOT. Mercruiser states that the WOT range for my setup should be 4400 - 4800 RPM.

Upon the advice of a Sea Ray dealer and the guy who fixes my prop, I bought and put on a 21 pitch prop before this season. This should have gotten me closer to 4600 RPM, which would be midrange of WOT.

The boat just didn't feel right with this prop; it almost feels like something is holding the boat back. Wide open, my numbers actually dropped - 37 MPH (GPS) @ 3900 RPM. Thinking it was a bad prop, I put my 23 pitch back; things did not get better, and the feel of dragging something heavy behind remains. So obviously there is an issue engine wise.

The only thing that is different fram last year was during the last run back in October, I hit something underwater that took a few hunks out of my prop. I ran back to the ramp at low speed because I was getting some pretty good vibrations from the prop. The other issue is some electrical gremlins that surfaced this year; you can read about that in this link:

http://www.clubsearay.com/forum/showthread.php?t=12066

Anyone have any ideas what I should look at or for??

 

[tobnpr]

Fuel restriction?

 

[SR Tech]

Is the fuel system MPI OR TKS?

Aside from you dragging a weight behind you, did you notice/hear any sputters or bogs?

If your saying that you hit the prop pretty good, allthough not to common, you could have a bent prop shaft. Or if you used the same flo-torq kit...but I hope you wouldn't.

A bad battery will also cause this, especially when using other accessories like trim or the stereo. The alternator can put out as much as it wants but a bad cell battery will NOT take the charge, therefore not giving you a recharagble circuit.

I will be able to help you more after you answer the first question

 

[rktktpaul]

Is the fuel system MPI OR TKS?

2bbl carburetor, so I assume its TKS

Aside from you dragging a weight behind you, did you notice/hear any sputters or bogs?

Other than my usual run-on problem when I immediately shut down the engine after coming off plane, nothing.

If your saying that you hit the prop pretty good, allthough not too common, you could have a bent prop shaft. Or if you used the same flo-torq kit...but I hope you wouldn't.

What would be a good indicator of a bent prop shaft?? I'm not feeling any vibrations using either the new or repaired old prop. And no, I did not change the flo-torq insert as my prop guy said it looked ok.

A bad battery will also cause this, especially when using other accessories like trim or the stereo. The alternator can put out as much as it wants but a bad cell battery will NOT take the charge, therefore not giving you a recharagble circuit.

I do have some electrical issues since I've installed my depth finder, but my battery was fine the first time I took the boat out on July 4th; this was after the battery sat in the boat all winter disconnected and without charging prior to first use.

As I stated in my other post ( http://www.clubsearay.com/forum/showthread.php?t=12066 ), my gauges suddenly had different "resting" positions after I put the instrument panel back during the installation of the depth finder gauge. Two months later my battery was completely flat.

I will be able to help you more after you answer the first question

Hopefully my answers will give you some more insight.

I gotta say, I really appreciate everyones help here. This is one of the best forums I've ever been a part of!!

 

[SR Tech]

Sorry for the late reply, been in Puerto Rico:thumbsup:.

I'm leaning more towards the flo-torq, as you know its made out of plastic.

Hitting something in the water while under way may have made the plastic catch spin inside the propeller.

Just sounds to me like there is a bit of play between the propshaft and the propeller. Which can only have one suspect. Try changing it out and see what happens.

"2bbl carburetor, so I assume its TKS"
Sorry that ones my fault, just assumed that it was injected, or had an enrichener. Its just a carb, no TKS.

When was the last tune up?

 

[mrsrobinson]

SR Tech, for a tech guy you speak/write very well...no offense to the tech guys out there. You should consider running/owning your own shop!

Edit:

Just looked at your profile "Sea Ray Technician/Now Service Manager"

Congrats to you...Now buy the shop.

 

[Gunn]

I'm leaning more towards the flo-torq, as you know its made out of plastic.

Hitting something in the water while under way may have made the plastic catch spin inside the propeller.

Just sounds to me like there is a bit of play between the propshaft and the propeller. Which can only have one suspect. Try changing it out and see what happens.

If the prop was spinning on the shaft, you'd think he would have seen a higher RPM, possibly overrevving the engine, but not going anywhere fast...? :huh:

This is a good one; good luck!

Tom

 

[SR Tech]

I didn't mean completely worn out, yes if the flo-torq was worn out to the point where it didn't catch the prop anymore then it would over rev. Nice catch:grin:

If just has a bit of play in there you will notice a difference in accerleration. Especially after shifting.

 

[rktktpaul]

Thanks!! That's a fairly cheap fix that I will try!!

Should I be worried about my gauges not zeroing out now??