1989 Mercury 100hp Outboard Bogs Down Upon Fast Acceleration

[shoots7066]

I have a 1989 Merc 100 hp 4 cyl. It runs great most of the time except when i try to take off fast out of the hole. when im going slow than try to ounch it (like if i were pulling a skier) it bogs down for a second than accelerates like normal. It does idle a little rough. I have pulled the plugs and they are pretty black. Is it possible the enigne is running to rich and i should lean out the mixture using the adjustment screw? the engine has a feature that cuts out the bottom tow cylinders below 1800 rpm (no low idle jets on the carbs. Any ideas on how to fix this?

Thanks

 

[eaglelakewally]

Re: 1989 Mercury 100hp Outboard Bogs Down Upon Fast Acceleration

I have an 88 model that runs similar, your plugs suggest it's running rich. are you running at a higher altitude than motor was last tuned too. I am not a mechanic so please don't take this advice as gospel it is just what I found helpful.! It wouldn"t hurt to check idle mixture but also the following items may help.
Check and adjust the accelerator pump(the thing with plunger on top). And as a quick test, with engine idling depress the plunger with flat screwdriver and it should make engine surge a Little. If leaking, may have bad diaphragm inside. it gives a little extra fuel to lower cyls. when accelerating from idle. Also I have replaced my plugs to l78v's they run a little hotter and seen to help burn the rich fuel mixture at altitude.

 

[Ace1948]

Re: 1989 Mercury 100hp Outboard Bogs Down Upon Fast Acceleration

I have a question about the the diaphragm does any one know where i can buy one?
Mine has a hole in the diaphragm.