Dry carbon fouled plugs 120 hp mercruiser

[matti5475]

So update. I pulled the carb apart to see if anything looked off and ripped the gasket, so f it, I'll rebuild it again. I did notice that the accelerator pump had a broken tab around the plunger, so now I want to make sure it's not in there floating around. Any suggestions on which carb kit is best, carb is mcm 165 1389-9562

 

[Grub54891]

To help prevent the gasket from ripping, I use a touch of vaseline on the gasket before installing. keeps it from sticking if it has to come apart again.

 

[matti5475]

To help prevent the gasket from ripping, I use a touch of vaseline on the gasket before installing. keeps it from sticking if it has to come apart again.

I will definitely give that a try. Thank you

 

[matti5475]

My carb kit came Wednesday and I did a rebuild. One thing I noticed was that the power piston was bent, which I think I did end of last season when I was all stressed out from it running like **** and didn't make sure it was seated right before cranking it down bowl cover. Took boat out yesterday and it ran good , but was bogging down at high speeds, like it didn't have enough fuel, so I ordered another power piston to eliminate that as an issue. To my understanding that controls the vacuum and even though I got it some what straight, I'm not confident it is working properly. And oh, the boat doesn't blow black smoke anymore.

 

[TyeeMan]

The accelerator pump (power piston) would have nothing to do with your bogging at higher RPM or vacuum. All the accelerator pump does is squirt fuel down the carburetor bores when you move the throttle lever. So when you pump the throttle right before you start the boat, the accelerator pump puts a good squirt of fuel down the bores. Also when you accelerate from idle to full throttle the accelerator pump squirts fuel to make that RPM transition smoother and more seamless.

 

[matti5475]

The accelerator pump (power piston) would have nothing to do with your bogging at higher RPM or vacuum. All the accelerator pump does is squirt fuel down the carburetor bores when you move the throttle lever. So when you pump the throttle right before you start the boat, the accelerator pump puts a good squirt of fuel down the bores. Also when you accelerate from idle to full throttle the accelerator pump squirts fuel to make that RPM transition smoother and more seamless.

This is what I was referring too. It's what controls the power valve by vacuum from what I have read.

 

[TyeeMan]

Oh, got it. Yeah I would imagine if that was bent that have an affect on something.
Good to hear your not blowing black smoke any more.

 

[matti5475]

Oh, got it. Yeah I would imagine if that was bent that have an affect on something.
Good to hear your not blowing black smoke any more.

I gave it another look before going out on the big lake tonight. I checked both filters, turns out filter on the carb had rubber pieces in it from when I checked the tank siphon. Swapped filter out and now the boat runs perfect. I'm still going change the power piston at the end of the season, and the fuel line too, just because they aren't in the best shape. Thanks for all the help boater!