1978 Mercury 50 hp

[tgpfloat]

I have a 16 ft star craft with a 50 hp mercury on it.
It had not been run in many years. HAs good compression, good spark, new tank, new fuel lines to and in the engine and new gasket set. She runs and starts like a champ. When I give it some throttle it seemed to have a slight skip, then picked up and was fine and ran great. next time out during full throttle it would bog down. Would idle and handle a little idle fine but bogs at heavy throttle?

Seems like a carb issue? Do I need a rebuild
This is my first boat
Thanks

 

[jarand82]

Re: 1978 Mercury 50 hp

I'd take the carb apart and blow compressed air through all the little ports.

 

[jeff_smith_0423]

Re: 1978 Mercury 50 hp

After being laid up, carb rebuilds are in order. They're pretty easy on that motor.

Check for any corroded wiring or cracked insulation, particularly from the stator. If you can, obtain a DVA multimeter and do the stator checks. Plenty of pros around here can help you interpret the results.

 

[tgpfloat]

Re: 1978 Mercury 50 hp

I bought the OEm manual for my motor, I am a little intimidated about removing and rebuilding the carbs. How do you adjust both of the carbs the same way so they are working together? I have heard horror stories about trying to adjust two carbs. I have no experiance with this.

I did find a wire with cracked insulation, I will try and figure what it does from the manual.

Thanks

 

[jeff_smith_0423]

Re: 1978 Mercury 50 hp

If they're like mine on my 85 were, the only thing "adjustable" is the idle mixture and that's a pretty easy procedure. I've never worked on multiple four-stroke automotive carbs, but these are synced with a plastic shaft that connects the two carbs together.

The "link & sync" procedure is a little more difficult, but there's a post floating around by Clams Canino that simplifies it a little more.

I was terrified to tear into mine the first time around, too. After reading all of the instructions about a hundred times, i decided to suck it up and just do it - at about two in the morning. I had 'em off, disassembled, and soaking in cleaner in about 30 minutes. As long as you're methodical, and have the right parts and tools, you'll be fine. I would order double what you need for gasket kits, and order an extra needle/seat set. In case you drop or lose something, you have the parts right there and you won't get set back a few days waiting for stuff to arrive. My experience with mechanical things is that when i get delayed, i forget things and I screw stuff up.

Good luck.