2002 Mercury 200EFI low on power?

[Toastedfilms]

S/N 0T565896

I've been having some engine problems hoping someone can help point me in the right direction.

So recently I've noticed my EFI seems to be running rough and is lacking power.

It always starts right up at the beginning of the day but seems to be running rich. It smokes more then it should and shakes pretty bad at idle. (I premix the engine 50/1)

After I run it for a bit I sometime have to advance the throttle to get it to start but not always

When I'm fishing tournaments and have my livewells full with a coangler it wont plane out unless my Co gets on the front deck. When I'm by myself it'll plane out but it still takes a minute. I'm running a 25p tempest plus. It seems like its getting worse and worse. When I first mounted the engine on the boat (a 2002 procraft superpro) it would jump right out of the hole.

It also seems to be lacking power on the top end. I'm only seeing 5100-5300 RPM and I can barley hit 60mph by myself and 57 with my Co.

I recently checked the compression with 3 different compression gauges and it was 125 on all cylinders.

I also changed the plugs and fuel filter. The plugs definitely looked like it was running rich. Once I changed the plugs it idles a bit better and started better after running but didn't help the planing or top end.

Any ideas on what it might be? I'm thinking maybe injectors need to be flowed or reeds possibly? Thanks for the help guys

[JOE54]

check see if tuner is loose or fell off, restricting exhaust

[Toastedfilms]

check see if tuner is loose or fell off, restricting exhaust

Can you elaborate on that I'm not familiar with how to check that.

[EuropeanAM]

Remove gearcase, reach up into driveshaft housing to see if the tuner can be moved around in the exhaust cavity (it should be firmly affixed and not move AT ALL).

[JOE54]

^^^^^

[Toastedfilms]

will do, Thanks guys!

[Toastedfilms]

Remove gearcase, reach up into driveshaft housing to see if the tuner can be moved around in the exhaust cavity (it should be firmly affixed and not move AT ALL).

just got done checking the tuner. It was not loose. Any other ideas?

[Toastedfilms]

check see if tuner is loose or fell off, restricting exhaust

just checked the tuner, it was not loose.

[Dalehill]

I have had similar issues. These guys were great in helping resolve the problem. Made trouble shooting the problem more difficult by inspecting the vst and bumping the float. Once they suggested that I connect a 6 gallon tank to the motor, began closing in on the problem. Corrected the float, fuel pump no longer starving. Come to find out the issue was with my onboard fuel tank. Motor runs great, awesome power each time I plane off.
2002 efi s/n ot444399

[Toastedfilms]

I have had similar issues. These guys were great in helping resolve the problem. Made trouble shooting the problem more difficult by inspecting the vst and bumping the float. Once they suggested that I connect a 6 gallon tank to the motor, began closing in on the problem. Corrected the float, fuel pump no longer starving. Come to find out the issue was with my onboard fuel tank. Motor runs great, awesome power each time I plane off.
2002 efi s/n Or 444399.

that could definitely be the issue. What did you have to do to the VST and how did you fix your fuel tank?

[Dalehill]

Blew compressed air back to the tank. Remove an extra fuel/water separator filter. The vst was actually clean. My bad bumping the float.

[Toastedfilms]

Blew compressed air back to the tank. Remove an extra fuel/water separator filter. The vst was actually clean. My bad bumping the float.

ill have to see if I have a extra filter, I don't believe I do. I wonder what's making mine run so rich.

[JOE54]

test air temp sensor as per serv manuel

[Toastedfilms]

test air temp sensor as per serv manuel

Will do!