Help with Merc20.

TinBoats.net

Help Support TinBoats.net:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

jshad

New member
Joined
Jul 21, 2013
Messages
1
Reaction score
0
Hello, I recently boat my first jon boat, it is a 1970 duracraft 1436. My father in law gave me a 1975 Merc200 20hp. When he gave it to me he told me it was having a problem pushing his old boat and that he had it in the shop getting gears replaced in the foot. I was thinking it may have been a cavitation issue, but now I think it may be the prop. I took it to the lake and it would do fine just over idle, but when I tried to accelerate I didn't gain any speed and the motor would go up in rpms.

I brought the boat home and did some research, so I marked the hub with paint and ran it in a barrel full of water. I was at about half throttle for about 15 seconds and went to almost full throttle a couple of times, but when I took the prop off the lines were still lined up. judging how bad it did at the lake I thought that I ran it long enough for the hub to slip. Is there a difference in running in open water and running the motor in a barrel? Or, could I have another problem. Any comments or help would be much appreciated, Jeremy.
 
I have a 74 20hp Mercury that was doing the same thing. I replaced the prop and it ran fine for about 15 minutes then it gave out on me. Turns out it was a bad drive shaft. It is in the shop right now. Its about a $200 job to get it fixed but once you get it fixed, it will run forever.
 
Top