Merc 350 MPI

Z

ZmmmZ

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Aug 26, 2013
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Hi,
I have 2005 Merc 350 MPI 300 HP, the engine has only 200hours on it and i have had it since new, i used to get 30MPH @ 3000 - 3200 RPM, recently i am getting 20 MPH @ same RPM, boat has a clean hull and engine is performing normal temp and oil are all fine. I feel it is drive related but not sure were to start as i have had a few simple drive issues with water cooling impeller and a few bad oil seals but i have always replaced with original pats promptly. Any clue were to start ?
 
Bondo

Bondo

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Re: Merc 350 MPI

ZmmmZ said:
Hi,
I have 2005 Merc 350 MPI 300 HP, the engine has only 200hours on it and i have had it since new, i used to get 30MPH @ 3000 - 3200 RPM, recently i am getting 20 MPH @ same RPM, boat has a clean hull and engine is performing normal temp and oil are all fine. I feel it is drive related but not sure were to start as i have had a few simple drive issues with water cooling impeller and a few bad oil seals but i have always replaced with original pats promptly. Any clue were to start ?
Click to expand...

Ayuh,.... Welcome Aboard,.... What Is the drive,..?? ya told Us 'bout the motor,...
 
alldodge

alldodge

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Re: Merc 350 MPI

ZmmmZ said:
Hi,
I have 2005 Merc 350 MPI 300 HP, the engine has only 200hours on it and i have had it since new, i used to get 30MPH @ 3000 - 3200 RPM, recently i am getting 20 MPH @ same RPM, boat has a clean hull and engine is performing normal temp and oil are all fine. I feel it is drive related but not sure were to start as i have had a few simple drive issues with water cooling impeller and a few bad oil seals but i have always replaced with original pats promptly. Any clue were to start ?
Click to expand...

Welcome

What Bond-o said and a drive serial number could help. If you smelled burt rubber, maybe the coupler, if not maybe the drive or prop.
When was the last time you checked alignment and changed drive lube?
 
Z

ZmmmZ

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Messages
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Re: Merc 350 MPI

AllDodge said:
Welcome

What Bond-o said and a drive serial number could help. If you smelled burt rubber, maybe the coupler, if not maybe the drive or prop.
When was the last time you checked alignment and changed drive lube?
Click to expand...

Drive lube changed less then 10hours ago with impeller ...
 
thumpar

thumpar

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Re: Merc 350 MPI

Is that the boat speedo reading or GPS? Since you can still get to good WOT it sounds like everything is fine.
 
alldodge

alldodge

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Re: Merc 350 MPI

Check you prop and see if you spun the hub. Pull the prop and see if the inside rubber of the prop looks damaged. If not put prop back on the drive, drive down, gear shift in reverse, put strap wrench around the prop and try to see if you can rotate it clockwise. If unable to turn, put a socket and breaker bar on the prop nut and see if you can turn it Clockwise.

If the prop turned, the hub is spun
If the shaft turns using a breaker bar the coupler is spun
If you here any grinding, drive needs work
 
Z

ZmmmZ

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Joined
Aug 26, 2013
Messages
5
Re: Merc 350 MPI

AllDodge said:
Check you prop and see if you spun the hub. Pull the prop and see if the inside rubber of the prop looks damaged. If not put prop back on the drive, drive down, gear shift in reverse, put strap wrench around the prop and try to see if you can rotate it clockwise. If unable to turn, put a socket and breaker bar on the prop nut and see if you can turn it Clockwise.

If the prop turned, the hub is spun
If the shaft turns using a breaker bar the coupler is spun
If you here any grinding, drive needs work
Click to expand...

Looks like the HUB was the issue had it replaced and will try this weekend.... thank you all will let you know how it performs...
 
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