1986 20 hp mercury problem

[jodum]

While traveling at approx 75% throttle the rpms went wide open and the boat speed dropped to zero. I cut the power to the outboard and attempted to get it moving forward again. As I applied the throttle slowly, the engine provided normal thrust but as I encreased power the motor again lost speed and rpms encreased. Something seems to be slipping as engine power is encreased. The manual shows a direct pinion drive in the foot so it must be the prop causing the problem. Any suggestions or imput to help.

 

[dkondelik]

Re: 1986 20 hp mercury problem

Afternoon jodum,<br /><br />from you description,it sounds as if the prop hub may have "spun" out.<br /><br />try using a marker to put locator marks on the pro and the prop hub.<br /><br />run the boat. look at the marks that you had drawn to see if the mark on the prop has moved reative to the hub. if yes, the hub has spun out. any prop shop can repair the problem. many boat shops/marinas have access to a prop shop. my local boat store can sen out a prop on tuesday and have it repaired and returned by friday.<br /><br />Good Luck<br />HAVE FUN!

 

[jodum]

Re: 1986 20 hp mercury problem

Klondik thanks for the information. The rubber seals on the prop looked melted which led me to beleive it was a prop problem. This is the first problem I have had with the motor so I have never had to work on it. I am in the electronics business and can work on anything with a transister but if it has more than two bolts I am lost. I knew I could find a forum somewhere to help.<br />Thanks again