94 Mercury 75hp loss of power.

[cvt88]

Alright guys here’s my issue...
1994 75hp mercury.
Seems like it is only running on 2 cylinders or fuel is not getting to the bottom cylinder. About 2 months ago I got it out on the water ran around 32mph around 5500 rpm and shot out the hole, now I’m getting 25mph around 4000rpm and hard to get out the hole.

Top 2 plugs are hot to the touch and the bottom is not, which is why I’m assuming it’s not getting fuel or firing.

I have a new stator, new switch box, new ignition coils, plugs and wires, new fuel pump, rebuilt and cleaned the carbs a couple times. New gas tank.

Does anybody have any ideas what could be going on?

Also the time it started with this problem,I was out on the water the motor would surge into full power and then bogg down for about a min then surge back in to full power kept doing this all the way back in. Now it just runs on what seems like 2 cylinders.

Please and thank you for all the help.

 

[shipoffools]

Check the fuel pump rebuild is simple a fairly cheap. I also ran into an issue a few years back where one of the plastic pins holding the pump diaphragms broke and found its way into the fuel line causing the kind of issue your describing. My motor is an 88 70hp.

 

[flyingscott]

Check spark and compression

 

[racerone]

Lot of new parts and big $$$- spent.-----Test compression-----Look at reed valves.-------If there is no fuel going into that cylinderk, it would also mean no oil.-----Get this sorted out before running it again !

 

[cvt88]

I just rebuilt this fuel pump today. Also I have compression reading 120-120-118 as of today. I’ve gone almost over every inch of this motor and can’t figure out why I’m losing power. Pretty much the only electrical part I didn’t change was the trigger because the ohm tested out in specs.