1978 Chrysler 45hp not sure if getting top speed

[Mm44012]

I have a 1979 Chrysler Sport Satellite with a 1978 45hp Chrysler outboard. With 2 people on and minimum gear it tops out at about 19mph. Any more than that and I am only getting about 10mph. The engine runs great otherwise. It has a 12.5 pitch prop on it and sits in the middle trim position. Any Idead?

 

[catfishcarl99]

probably normal. I have a 17' 1989 spectrum 1700 with a 89 original force 50. with 2 people im barely hitting 10. 25 with just me.

 

[jerryjerry05]

How big is the boat?
How you checking the speed?

To figure out if the boat/motors running correct, you'll need a tach.
Your motor should rev up to about 53-5500 rpm's at wide open.
That's with a minimum load.

You check the speed with a gps? Some phones have that ability??
The boat speedo could be wrong?

You sure that both cyl. are firing?
These 2 cyl. motors can run fairly well on just one cyl.
Do the cyl. drop test. start the motor and pull one wire at a time.
Any difference?

 

[Mm44012]

I have done the drop test and everything. I have been through the entire motor. I gps check the speed. I have a 10 pitch coming tomorrow. I'll hopefully have it out Monday to test it.

 

[jerryjerry05]

They sell, Tiny Tach or something similar.
Under $25
With the tach you'll know exactly where your at?

Boat size?
One fella was wondering why his 24ft.pontoon wouldn't go past 20mph.
His 45hp. just didn't have the power.

Do a comp test?