Low RPM & Speed with Merc 200

[Duke01]

I took the Welly out on Lake Erie last night, it had been a month since I had started the engine and 3 months since I had her out on the water (the motor yacht always seems to get more attention - no surprise there). The old Merc started right up, ran smooth, all good except I maxed out at 20 MPH and 4000 RPM. Tried 4 times and never exceeded 20 MPH. I pumped the bulb for a 2nd and 3rd time, same results. So, I am thinking maybe a bad fuel pump, or perhaps a possible leak in the fuel line? I am going to install an inline fuel pressure gauge and check the tank vents too.

It is a 1980 motor, so the fuel pump (88853A1) does net seem to be available (?)

I welcome any input from the group.

Thanks, as always, Duke

[phatdaddy]

Easiest thing to do first is check fire on all cylinders, check plugs and compression while at it.

[THEFERMANATOR]

Sounds more like a weak stator or switch box to me. If it was the fuel pump, it eould normally take off abd then fall on its face as it sucks all the fuel out of the bowls. Have somebody pump thr primer bulb while it won't turn up, if it picks up rpm's then I would look at the pump. Those early pumps are nla, you would have to try and rebuild it, or go to a newer style pump. To me this sounds most like a high speed stator on its way out.

[Duke01]

Thanks guys, after doing more research, it does sound like the stator. I will take her out again after I check the plugs and install a fuel pressure gauge and new fuel filter. Then pump the bulb as you suggest Ferm and see what the impact is, if any.

Stator was replaced in 2011, along with the switchbox by the previous owner. I thought that I had that part behind me...perhaps not.

[spareparts]

compression test, spark check, fuel check, report back with results

[Duke01]

I will perform those checks this weekend, weather permitting.

Thanks, Duke