2000 Mercruiser 5.0 220hp question

[ewpvic]

Ran this engine yesterday (it's in a Bayliner 2152 Cuddy). GPS speed was a mere 36mph at WOT (~4500). Seems quite tired to me. No gear, 3/4 fuel and just me and wife aboard. Boat lived most of it's life in dry storage.

Where to start?

Engine sounds and performs very smoothly (carb engine, 19p prop). Temp stayed at 165 no matter what I did. NO throttle hesitation. I just thought that 40+ would be a breeze.

Thanks

 

[Scott Danforth]

something is amiss, as that boat when new would have been close to 50mph http://www.boatingmag.com/boats/bayliner-2150-capri

with that stated, you are not hitting WOT. your RPM's should be a bit higher. My 5.0 would push my searay at 50mph at about 4800 RPM just like the boatingmag dot com test of your boat in the above link

where to start:
weigh the boat. if your dry weight is over 2850 or your wet weight is over 3200#, you probably have wet foam.
do a compression test. most of your cylinders should be around 175psi that is where my 2002 5.0 was.
check your fuel system for water, debris
check to make sure your throttle plates are opening fully when the throttle is all the way forward.

 

[ewpvic]

10-4. I will start with the simple stuff first. Thanks. I figured I should be at LEAST well into the 40s with this power plant.

 

[MikDee]

As Scott said, physically check your linkage to see if your throttle plates are opening fully? Aside from that check your timing, you should be overreving with that 19" prop on there?

 

[midcarolina]

Also If all the above comes up good, while running on muffs pull one plug wire at a time and see if there is a noticeable change, If you pull a plug wire and the sound of the engine does not change that cylinder is not firing........would not be the first time a motor seems to be running right but is running on 7 cylinders.

 

[ewpvic]

My prop is a Quicksilver 1912P17.