Loss of top speed and hole shot.

lzybasterd

New Member
Aug 4, 2009
4
Heya all and thx for you time.. The last few times I have gone out on the lake I have seemed to have lost about 15mph and plane 2 to 3 times slower than I used to. So in June of this month boat would plane in a few secs. now it take like 10. Also loss top speed was around 50-55 with 4 people on the boat and full tank of gas, now its 40mph. One week the boat ran great next week go out and have the power loss.

We have a 5.0l Alpha one drive 220hp with 19 pitch alum. prop.
2007 195 sport sea ray.

So after the power loss we tried a few things.
First we changed the plugs and the fuel seperator. that didnt work.
Second went from the 19 pitch alum 3 blade prop to a 22 pitch 4 blade ss prop. that didnt work either.
third we had a guy come look at the boat and take a drive with me. He was at a loss too.

The WOt is at 4700 rpms. So we are clueless to whats wrong and would love any help you can give.

We are getting the right Wot at 4700 rpms
 
It is unclear from your post as to whether or not your boat stays in the water - ie; does it sit in a slip at a dock? If so, have you considered if you have growth that has attached to the hull bottom? Maybe you just need to clean your bottom.

Additionally, I believe the standard prop for that boat and engine combo was a 21" stainless.
 
A clean bottom is always a good thing! :grin:

Can you be more specific as to what prop you have? Is it a rubber-hubbed prop? If so, it could be slipping. Although, typically it will over-rev.
 
We had it slipped for about 2 months. But we had the boat cleaned and it still didnt help the problem. Even after the 2 months in the water dont think there was any real grow to slow down the boat. The prop is not a rubber hubbed one.. a plastic part slips in the back and a metal part goes in the front of the prop and slides into the plastic piece. then the lock washer and brass nut..
 
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Oh, when in '07 did you buy it? You would have had at least a 2 year warranty.

Do you still have the original prop? The 3-blade SS, 21"?

If you're getting the proper WOT RPM, which you stated you are, and you're trimming properly, the only other thing I can think of is something that's causing an extra drag. How's the condition of the prop?
 
Well, if the engine is turning the proper RPMs (assuming tach is correct) and there is no external drag on hull or prop, I can only think of one other thing... and it isn't pretty. It's also so very unlikely in a newer boat that I didn't think it was worth mentioning before: engine/drive coupler. It's an intermediate piece between engine and drive - it's a rubber coupling. It could be slipping. BUT, it will typically make a noise and it will also typically allow the engine to OVER-REV. You didn't mention either of those problems, so... I think I've played all my cards. W/O any other information, I can't think of anything else. Sorry.

I assume because you didn't answer that you are out of warranty?
 

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