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dtcohen

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"Hi, I have a 1987 sea ray sea

"Hi, I have a 1987 sea ray seaville with a 4.3 V6 and an Alpha one drive. When I have it at full throttle the engine is only turning about 3500 rpm and the boat is running around 45mph. Is that normal? It just seems like it should turn more RPM's. It has a stainless 3 blade prop on it, I am not sure of the pitch."
 
I would like to have that on m

I would like to have that on my 4.3L! Your boat must be a 17'. What is the HP rating and how much does it weigh?

If your engine has a 2 BBL carb it should run about 4400-4500 RPMs. A 4 BBL will produce 4700-4800 RPMs w/the right prop.

Did you look on the prop for some numbers?

The prop may be starting to slip on the hub. A prop shop could tell you if it is.

I run a 14.25" 19 Pitch SS prop on my 2 BBL carbed 4.3L and can get it up to 45 MPH @ 4600 RPM's on calm water by trimming out the OD.

Is the boat hull nice and clean? Tach could be off.
 
"The boat is actually 21'

"The boat is actually 21' and i believe the HP rating is 205

It has a 4bbl quadrajet carb

The hull is clean and has been waxed

The 4.3 is a pretty stout little motor, It will pull my 230lb friend out of the water on a wakeboard without too much strain

My grandpa bought the boat new in 87 and it only has about 300 hours on it and it completely stock

Next time I am in town (I am at college right now) I am going to take it to a local boat shop and have him take a look at the prop, adjust the valves, and check a couple other little things."
 
"Put in the boat's loaded

"Put in the boat's loaded weight and feet above sea level to get the prop's pitch. I used 4000 lbs.

<center><table border=1><tr><td>http://www.marineengine.com/discus/icons/mime_msexcel.gif""" align=left alt=""application/vnd.ms-excel"">prop finder
[url=""][b]Copy of Copy_of_Boat_Speed_Finder-79780-193827.xls[/b][/url] (26.1 k)</td></tr></table></center>"
 
"I have no idea what the boat

"I have no idea what the boat weighs, I guess I will have to look all of that up when I get home

Thanks for the spreadsheet"
 
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