Just rebuilt 1994 Johnson 50hp

[John Wiegerink]

I just completely rebuilt my power-head(bored, new pistons, rings, seals, gaskets, etc.) I removed the VRO and installed a mechanical fuel pump. I also had a set of brand new 40hp carb ready for mounting and stuck them on the motor. Now, you may be scratching your head, but I had my reasons for doing it. First, I had problems with the VRO and then with the motor. The reason for eliminating the VRO. Second, the motor never ran right from the day I bought it and I suspected it was a carb problem, but could never find it. I even rebuilt the carbs twice. The 40hp carbs have a smaller throat, but that's okay by me and it might mean a little better fuel economy. The questions I have is: For fishing would I be better off with the stock 12 1/4 x 15 prop or go to a 13 1/4 x 13 or so prop. I want to troll slow and am not as concerned about high speed running. I have a 16.5 ft aluminum Sea-Nymph boat and before the rebuild I could never get the idle down enough(1000 rpm was as low as I could go) and keep the motor running to troll slow. I ran it on muffs and it runs fine, but I haven't taken it to the lake yet. I'd like to get the prop first as the old one is pretty ragged. I would guess I should treat this motor as a regular 40hp now.

 

[Silvertip]

Re: Just rebuilt 1994 Johnson 50hp

A 13P prop regardless of diameter on that motor is not suggested. Been there and done that. I happen to have owned a rig similar to yours and found the 15P to be the best all around prop and this engine would troll down down to less than 2 mph. Proper link & sync and idle mixture settings are required for proper idle and those adjustments "must" be made with the engine in the water as there is no exhaust back pressure running on muffs.

 

[John Wiegerink]

Re: Just rebuilt 1994 Johnson 50hp

Silvertip,
Thanks for the reply and the information. I just thought, since I was running more toward the 40hp range with the smaller throated carbs and top speed isn't a big priority, that the 13P prop might be more toward my liking. I guess I'll stay with the 12 1/4 X 15 standard prop then. I think after this rebuild the engine will troll much better. I've been all through the linkage/carb/tuning/new thermostat deal with this motor and nothing worked. Like I said, this thing never idled right from the first day I bought it and I bought it brand new. I could never get it to idle/troll below 1000 RPM in the water. I even took it to the most reputable and largest outboard repair shop in Grand Rapids and it cost me over $350.00 to have the carbs gone over, a new thermostat, the linkage adjusted and all the other BS they did. The results were no better than when I did all those things myself following the OMC repair manual. That's why I ditched the original 50hp carbs and stuck the 40hp set on the power-head. That might be stupid, but I suspect there was just not something right with that carb setup.