Re: 1979 mercury classic fifty dies when given a load
What do you mean by "refurbished"? When a motor dies under load, it can generally be linked to fuel related issues. The other thing to check is your prop hub. A spun hub can cause issues as well. However, 3 years on a rebuild is awhile, especially if it wasn't well cared for after the rebuild. If you can get it in the water at the lake and run it, try squeezing the primer bulb while in gear. If the RPM's pick up as you squeeze the primer bulb, you have a fuel related issue.
Also, make sure your gas tank vent is open. My motor will run on muffs with the vent closed, but in the water in gear it won't even try with the vent closed.
Note: My suggestion above is based on my assumption that most of the electrical must be good if it is running well on muffs. I'd also recommend to put it in a large barrel full of water and run it. In a barrel, it won't hurt anything to run it at higher RPM's. Just make sure you don't run it above idle speed with only the muffs. The barrel full of water will help simulate some load from water pressure being on the lower unit. I would try that and see if you can get it to run above idle.
