Volvo Penta 5.0 GL over reving

C

CSV

Cadet
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Aug 20, 2011
Messages
6
I have a 2006 Glastron gx205 w/ a Volvo penta 5.0 GL. The prop is 14.25x21 3 blade aluminum. The motor only had about 15 hours on it. I bought this boat last year. When I bought it the tach was sent out for repair. With 2 adults & 3 12 year olds and a full tank of gas I will bury the tach with the throttle open and out drive trimmed up. I believe the tach marks up to 6000 rpms, not for sure. Last time I took it out I didn't have a gps but speedo said 46 mph.

Since the tach tops out I didn't want to hold wide open, but think I could have hit 50 if I left it open.

Does this sound like I need more prop or the tach is off? Taking it out for a long weekend next weekend and wondering if I should try a 23 pitch prop

Thanks
 
M

Maclin

Admiral
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May 27, 2007
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6,761
Re: Volvo Penta 5.0 GL over reving

Sounds like the tach is off, set for wrong number of cylinders maybe.

50mph with 1.6 drive ratio and 21p with 12% slip would be 4570rpm.
 
M

Maclin

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6,761
Re: Volvo Penta 5.0 GL over reving

I bet you are good to go as is is.
 
M

Maclin

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Re: Volvo Penta 5.0 GL over reving

Sorry, I keep hitting SUBMIT instead of PREVIEW.

A tach set to 6 cylinders on an 8 cylinder engine will read 6000rpm when actual rpm is 4500.
 
M

Maclin

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6,761
Re: Volvo Penta 5.0 GL over reving

So, your boat is in better shape than I am.. :)
 
C

CSV

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Aug 20, 2011
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Re: Volvo Penta 5.0 GL over reving

Thanks for the reply, is there a way for me to check the tach?
 
Bondo

Bondo

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Re: Volvo Penta 5.0 GL over reving

CSV said:
Thanks for the reply, is there a way for me to check the tach?
Click to expand...

Ayuh,..... There may be a switch on the back that can be switched,...
Or,...
Compare it to a Known Shop Tach...
 
C

CSV

Cadet
Joined
Aug 20, 2011
Messages
6
Re: Volvo Penta 5.0 GL over reving

Thanks for the replys. I will check the tach, hopefully it's just a switch!
 
C

CSV

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Joined
Aug 20, 2011
Messages
6
Re: Volvo Penta 5.0 GL over reving

Bond-o said:
Ayuh,..... There may be a switch on the back that can be switched,...
Or,...
Compare it to a Known Shop Tach...
Click to expand...

The gauge is a Faria and has a dial on the back with numbers 1,2,3,4,5,6. It is set on 2. Seem right to anyone? Probably post in another section?
 
K

kiowapilot

Recruit
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Jun 27, 2012
Messages
5
Re: Volvo Penta 5.0 GL over reving

I Just got an 03 Glastron with the 5.0. Took it out on the water for the first time and had the same issue. Never went to WOT due to me worrying about over revving it. On trim was hitting 48 on the speedo with RPM showing 5,600 at about 3/4 throttle in smooth water. 2 adults, 1 kid, full tank of gas. Prop is 3 blade 14 1/4, 21 aluminium. Perhaps I should check my tach too.
 
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