Engine Bogs Down Under Load

[IslandDean]

I have a 1996 350 Mercruiser engine which bogs down and loses power under load. Revs fine at the dock but bogs down on water when it hits 1,800 - 2,000 RPM. Have changed the fuel filter, checked the tank for water/debris and am heading over to get a fuel pump and new fuel line. Long list of other items the mechanic and I have tried. He has essentially threw his hands up in the air and said no mass! Any suggestions appreciated.

 

[Bondo]

Ayuh,.... Welcome Aboard,...... What carb,..?? Efi,..?? Mpi,..??

 

[IslandDean]

Thanks. Believe the carb is a Weber. Had it sent out for a rebuild last year. Worked for the season.

 

[Bondo]

Thanks. Believe the carb is a Weber. Had it sent out for a rebuild last year. Worked for the season.

Ayuh,..... Read the spark plug's color, 'n see if it needs rebuildin' /cleanin' again,.....

If it picked up some crud, 'n is goin' lean, you can smoke yer motor in minutes tryin' to really Run it,....

 

[IslandDean]

Got it. This has been an ongoing problem since last fall. Changed out the plugs a couple of times over last 18 months and they were pretty dark the first time. I am going to install the new fuel pump, filter and new fuel line and take it out for a sea-trial. Next step will be to have the carb rebuilt again. Thanks for you help.

 

[Rick Stephens]

All it takes is a little crud in the jets and a Weber stops running. Easiest carburetor to clean ever made.

 

[IslandDean]

That will be my next post once the fuel pump is installed and still have the same issue...how to rebuild a Weber carburetor. I sent it out about 18 months ago to get rebuilt and if that is still the issue, I will seek guidance from you folks and do it myself. Thanks for reaching out.

 

[IslandDean]

These forums are great. Not sure what it is like in your part of the world but her on the west coast of Vancouver Island you cannot beg a marine mechanic to work on your boat. A few guys who work out of their yard and one shop that works on outboards here but you cannot get a call back. Guess its either COVID or "mammas don't let your babies grow up to be marine mechanics" in these parts.

 

[Paintman1960]

lol,

 

[Rick Stephens]

That will be my next post once the fuel pump is installed and still have the same issue...how to rebuild a Weber carburetor. I sent it out about 18 months ago to get rebuilt and if that is still the issue, I will seek guidance from you folks and do it myself. Thanks for reaching out.

I'd have skipped the fuel pump and gone right to cleaning the carb. Get a kit. Can use Weber or Edelbrock 1409 kit in it. It takes apart so easily kind of hard to make a mistake that way. Don't switch up the jets. Not sure on the Weber, but not supposed to use carb cleaner on the Edelbrock version. It has a coating that washes off. They say use simple green to get it clean. Run every passageway with a heavy fishing line or wire. Compressed air to make sure it is open. There ain't much else to it - - cept making sure the float heights are perfect.