92 Mercury 50 HP will not accellerate

[arild_johannessen]

Bought myself this engine some weeks ago, and the problem is that the engine suddenly would not accellerate beyond appr.3000 rpm.
It idles smooth,but runs a little bit weak maybe?

Previous owner had it to workshop, they changed fuel-pump,power-pack and rebuildt the carbs,no difference.
He would not spend more money on it, so I bought it,thinking that this problem could be solved, but now I am really
starting to wonder.

I have now done all the DVA-testing like the CDI-troubleshooting says ,using the CDI DVA-adapter,and it seems that
all values are inside spesifications.

Here are the values (cranking): STATOR DVA: low speed 245V(connected) 274V(disconnected)
high speed 52V(connected) 46V(disconnected)


Stator resistance: lowspeed-521 ohm highspeed-27,6 ohm


Trigger DVA : 8,5V connected and 12V disconnected on all 3 cyl. Resistance on all are about 1175 ohm

Powerpack DVA to the coils are about 240V at idle.

Have done carb and ignition sync, set the timing correctly,compression is 112psi-115psi-119psi (1 2 3)

I am lost here,anyone with some good advice here,will be much,much appreciated.
Have tried with the 2 yellow stator wires disconnected,no difference.

 

[racerone]

Perhaps the exhaust tube is plugged ??

 

[arild_johannessen]

Perhaps the exhaust tube is plugged ??

Had the lower unit down,looks good, and air bubbles are coming out from propeller housing at idle in tank.

What about inside the engine,adaptor plate,anything there that cause something like this?