97 Mercury 125 HP has low top speed

[Morpheus78]

I opened up my setup this past weekend for the first time. I have a 17 foot center console and the engine on it is a 125 Mercury. This thing should FLY!! I was guessing id get 50mph on it, but the GPS says between 32 and 34 mph. Anyone know any reason why this might be?

 

[Bondo]

Re: 97 Mercury 125 HP has low top speed

Ayuh,... Did you trim it out to a Flying attitude,..??
What rpms did it top out at,..??

 

[Morpheus78]

Re: 97 Mercury 125 HP has low top speed

I need to fix my tach...its not working...so I dont know what RPM its at. Hopefully this weekend ill get that working

How do you trim it out to a flying attitude? Right now my engine is trimmed all the way down as far as it will go...should i trim up?

 

[Tacklewasher]

Re: 97 Mercury 125 HP has low top speed

I need to fix my tach...its not working...so I dont know what RPM its at. Hopefully this weekend ill get that working

How do you trim it out to a flying attitude? Right now my engine is trimmed all the way down as far as it will go...should i trim up?

Yeah. You need to trim up some. As you trim up, you lift the bow and will pick up speed. Keep trimming up until you either a) slow down, b) porpoise or c) ventilate.

But to properly set up your boat, you need a working tach.

 

[steelespike]

Re: 97 Mercury 125 HP has low top speed

Trim out slowly and let it settle.

 

[Morpheus78]

Re: 97 Mercury 125 HP has low top speed

b) porpoise or c) ventilate

What does this mean? Sorry...im a newb.

 

[Bondo]

Re: 97 Mercury 125 HP has low top speed

Ayuh,... b) is when the bow hops up,+ down,... Chinewalking is side to side....
c) is the prop looses Grab,+ Revs til you drop the throttle to rebite...

 

[Morpheus78]

Re: 97 Mercury 125 HP has low top speed

Thank you everyone...im taking the boat out tomorrow or monday and will apply the proposed suggestions and post back my results.

I did my compression today also 140, 140, 145, and 140 ... looking good there.

 

[Morpheus78]

Re: 97 Mercury 125 HP has low top speed

Ok, i did what everyone said...it does make a difference. The boat does 38 - 40mph now on a nice day with little wind. Still think it should be faster though. Gunna make sure it has the right prop on.