3.0L not running right

[Bonanzadave]

97 Sea Ray with the Mercruiser 3.0L Alpha 1. Seemed to be OK last season and I winterized it like I have for the last 15years. Stabil fog in the cylinders and down the carb and some startron and seafoam in the gas.

It wont rev to 4k rpm underway. With the prop disengaged it revs to 4k then starts to break up to 5k on up.Top speed is only 34 mph and I swear it use to go over 40mph.

1. Put in new plugs AC 42LTS
2. cleaned the fuel screen in the side of the carb.
3. pulled the cap and rotor for inspection. Seemed ok.
4. Drained all the gas. Put in 12 gal of 91oct non oxy gas.

Marginal if any difference. Time to pull the carb ???

Im in the Twin Cities south metro. Thats MN. Thanks for any help.

Dave

 

[alldodge]

Probably a mistype, but MR43LTS
Timing 10 BTDC

winterized it like I have for the last 15years

Start with a compression test

 

[Rick Stephens]

And if it has never had a carb rebuild, 15 years is a long long time for a boat carburetor to go without a complete go through.

 

[Bonanzadave]

Probably a mistype, but MR43LTS
Timing 10 BTDC

I had 43s in it but the carb cover says 42s gaped at .035

And if it has never had a carb rebuild, 15 years is a long long time for a boat carburetor to go without a complete go through.

Its actually been 21 years and I been running good old ethanol blended 87oct pump gas in it. Any good sources to guide me through the process...

 

[Rick Stephens]

Its actually been 21 years and I been running good old ethanol blended 87oct pump gas in it. Any good sources to guide me through the process...

Mercruiser Service Manual. Online is free at boatinfo.no There are a number of places that sell the hard copy. It is the essential tool for working on your engine and drive.

 

[Bonanzadave]

Mercruiser Service Manual. Online is free at boatinfo.no .

Ive been looking at it. It does say 43LTS even though my carb cover says 42. I think Ill pull the carb. Where do you get gasket sets or other carb parts ?

 

[Rick Stephens]

Has a Mercarb on it.. not sure there is an automotive kit available for them. Someone else may know. Otherwise, both Sierra and Mercruiser make kits for the Mercarb. They are available from most anywhere including iBoats.

 

[Bonanzadave]

They are available from most anywhere including iBoats.

http://ww2.iboats.com/Carburetor-Ki...8556710--session_id.976847342--view_id.187703

This looks like the closest kit for my carb. Can anyone (carb builders) confirm that the Sierra 18-7070 will work on a 1997 3.0L mercruiser

 

[Rick Stephens]

I think you are safest posting your engine serial number to confirm kit number. The best resource is usually the Sierra parts catalog and it is solely based on serial number, not year manufacture.

 

[alldodge]

Look at the bottom of the page in the link you posted, there is a list of carb numbers. Look on your carb for the same number stamped or on a tag

 

[Bonanzadave]

Thanks guys. Got it ! I changed the stone filter in the fuel pump and did a carb rebuild with a mercarb kit from mikes carburetors. Watched his video a couple times which was very straight forward. I had a can of berrymans carb dip which bubbled the black paint so I just stripped it to bare aluminum. I put the jets and venturi in a ultra sonic then reassembled it. Everything was in the kit.

It now runs better than it ever has !!!

"Summer on the water.....some are not."

 

[Bt Doctur]

AD, depending on the SN , its 1 BTDC , 1 ATDC or 2ATDC

 

[Bonanzadave]

AD, depending on the SN , its 1 BTDC , 1 ATDC or 2ATDC

Sorry Doc, I have no idea what that means......

 

[alldodge]

AD, depending on the SN , its 1 BTDC , 1 ATDC or 2ATDC

I have no idea what that means

The different settings depends on your serial number that is shown in manual 26 and starts with motors year 1998.

I did mis-typed the wrong timing, it should have been 1 BTDC and this is assuming you have an EST distributor (manual 13). If you have points or DDIS then its set at 8 BTDC