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lack of power under load

TKO2013

TKO2013

New member
Soooo... the 95 Merc Magnum 350 with the 4bbl weber carb just isn't running quite right. When the boat is running in dry dock it starts and runs flawlessly revs up to high rpm with our hesitation but when the boat is in water under load condition its like a slug in the water! Some one suggested to look at accelerator pump in carb. I didnt exactly tear everything apart but did look down the carb to see if it was getting a healthy shot of fuel when throttle was down and it seems okay. But the boat takes a longggg time to get up to speed theres no "hole shot" but once its up at full speed she hums along a fine 50mph.
anyone have any thoughts on this?
Thanks
 
Ayuh,..... Have the cap, 'n rotor ever been changed,..??

spark plugs checked,..??

Inspect the contents of the fuel filter for anything other than fresh clean gasoline,.....
 
new cap new rotor new plugs... several fuel/water seperator filters no water... even the module inside dis cap was changed. its odd
 
oh ya... when I first got the boat it ran fine.. then a new starter new plugs and wires. then *&!* started to happen
Click to expand...

Ayuh,.... Then backtrack, 'n redo yer repairs, ya screwed something up along the way,.....
 
Last year i was helping a nieghbor with running issues under load in the water and after much parts swapping (ignition parts) and carburator... it turned out to be the starter.
I did not find this he did. I forget why he swapped the starter now but the boat then ran properly. I do not have an explanation what was wrong with the starter only he swapped it and the issues went away...
 
Thanks for that.. but the starter gave up the ghost a couple of years ago and was changed out already.. bloody boats! haha
kghost said:
Last year i was helping a nieghbor with running issues under load in the water and after much parts swapping (ignition parts) and carburator... it turned out to be the starter.
I did not find this he did. I forget why he swapped the starter now but the boat then ran properly. I do not have an explanation what was wrong with the starter only he swapped it and the issues went away...
Click to expand...
 
Your statement reminds me of my days of my youth..........long time ago

When I was first learning about car engines and always messing with points and wires and spark plugs........even when I may have had a spark plug wire crossed the engine seemed to run smooth as silk when in neutral. Then once in gear it would not so much.........typically you would get a back fire of some sort.

Not saying you are experiencing a back fire.

As with another thread you may want to make sure you are getting full secondary fuel and full timing advance.

Your discretion sounds like a large barge that would be under powered and takes a long time to plane off......
Also a boat soaked with water or covered in grass on the bottom......

Any other activity prior to this occurring?

It would not seem that a cap or rotor or spark plugs would cause this condition unless the cap is messed up internally.

If you have the old parts try a quick swap of the cap at least.

Also did you seat the rotor assembly properly??
 
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