1985 Mercury Black Max

[cssulliv]

I just put the boat in the water today for the first time in over a year and the motor runs very sluggish and seems bogged down whenever I put it into gear.

It starts up and idles great and it restarts great. I actually got it up on plane once and probably reached 30 knots but it only did that one time.

My average speed was probably 10 knots. Mostly when I put the throttle down it would seem like it wanted to get up to speed but would then sputter out and stall if I didn't let off the throttle. So, I pulled back and let it do its thing hoping it would come around but no luck....didn't get it up on plane after that.

Also, the engine seemed to be more responsive if I trimmed it up while I was giving it gas. It was not very responsive at all when it was trimmed all the way down.

I've read some similar posts and it seemed like they all had a carb. problem. However, the fact that I actually got it up on plane once leads me to think it may be something else.

Any suggestions?? Thanks!!

 

[DixieBoatN]

Re: 1985 Mercury Black Max

I had a similar problem with my 1985 Black Max v150 xr2, although it was not as drastic as yours. I started with the simple stuff first. I replaced the water separating fuel filter and the inline fuel filter. I took it back out on the water and problem was solved. I bought a spare set of filters to keep on board in case it happens again. You can try to verify if it is fuel related by pumping the fuel bulb when it happens. If pumping the bulb stops the problem, then it is fuel related.

It is either a fuel or spark problem. If you are like me and don't know when the last time the fuel filters were replaced, do those first because you are due anyway. If that does not resolve it, then start looking at the bigger things like fuel pump, carbs, ignition system, etc...

Someone else can/will elaborate more on how to troubleshoot those other issues.

 

[thedavel]

Re: 1985 Mercury Black Max

The first thing I would do would be to clean the carbs. Chances are there is something plugged and not letting the fuel go where it needs to go. I have a Mariner 175 that sat for a few years, and mine did the exact same thing. I cleaned the carbs, put a fuel/water seperator on it, and cleaned the tank and haven't had any trouble since.

 

[jt1111]

Re: 1985 Mercury Black Max

I just had a similiar problem with a 1985 black max 150. I cleaned the carbs, checked ignition, flushed fuel tanks, and got pretty frustrated. What I found was the needle valve in 5 of the 6 floats had wore a divet in the float. This cause the float to not completely seal the needle valve. I carefully bent the metal tabs on the floats to reset the flaot levels so they would seal and flow fuel properly. Problem solved. The motor runs awesome now.