1977 Mercury Outboard 200 20 HP

[Flyingchef84@gmail.com]

Hello, i have 20 hp mercury outboard. I went to the lake and i run it from slow to fast on gas but the speed stay the same. at one point is going fast but suddenly is lost of speed and the RPM /throtle on engine is go high (high on throttle but seem the propeller not going faster) Fell like you lost your clutch/ gear on the car. Need help...Thank you..

 

[gm280]

Re: 1977 Mercury Outboard 200 20 HP

With the limited amount of info you posted it could be any number of things. But I would check the prop to see if it has come apart from the center section first...

 

[Flyingchef84@gmail.com]

Re: 1977 Mercury Outboard 200 20 HP

With the limited amount of info you posted it could be any number of things. But I would check the prop to see if it has come apart from the center section first...

Hello thank you for the reply..I check the propeller and is good. I spin it around and is work find. Should I take out from the shaft ?? the engine is running fine when i place forward gear is moving and when I add more throttle gas the engine is going fast but the boat is at the same speed when lower throttle. Seem like the propeller is not synchronize with the engine.

 

[CharlieB]

Re: 1977 Mercury Outboard 200 20 HP

With boat boat on a trailer, or the motor on a SOLID stand,

REMOVE the spark plug wires to ensure the motor cannot start.

Shift into Forward gear

Wearing sturdy shoes, no flip flops, step down on the prop and turn the motor over. You'll have to step on the leading edge of the blade on the Port side of the motor.

Does the motor turn over in direct relation to the prop or does the prop seem to 'slip' on the propshaft?

Another proven method is to scribe a line across the prop, from one side of the barrel (outer edge) across the nut to the other outside edge. Run the boat, then check your line to see if it is still lined up. If not, take off the prop, either replace it and call your local prop shop and ask what it costs to re-hub your prop.

If you can afford it, it is ideal to do BOTH, then you always have a spare good prop. A spare prop can save a weekend if you trailer very far and bang a prop, bolt on the spare and keep fishing.

 

[Flyingchef84@gmail.com]

Re: 1977 Mercury Outboard 200 20 HP

Thank you for the help. By replacing the propeller is work as a charm now. I am apologize just say Thank you now.