85 blackmax lean sneeze at idle - mid/top end is GREAT though

[CamaroMan]

Took boat out for a test.. set pri pickup at 10 degrees ATDC.. verified carbs all 100% closed at idle.. warmer it gets the worse it gets..

idles, sneezes - now and then it stall and fires up easy and sometimes struggles to restart..

At one point I felt the sneeze blow back thru air baffle against my hand while i was trying to tweak the timing and carbs to see if there was a sweet spot. I guess this indicated bad reeds??

I found an entire reed plate with carbon reeds used for 80 bucks - any thoughts?

Something else I can check? All the small hoses between carbs / etc are in good shape. I rebuilt the carbs 5 months ago-..

 

[Dukedog]

motor?.. if a V6 WH gaskets are cheap.. do tha carbs again..

 

[Chris1956]

OK, lean sneeze at idle, OK above idle...suggests idle jets/passages are dirty, or idle mixture is mis-adjusted.

Some of those early V6 Mercs had fixed idle jets. Those must be very clean to work correctly.

Also, check for airleaks on carb bases and other gasket spots in intake stream.

 

[Dukedog]

Took boat out for a test.. set pri pickup at 10 degrees ATDC.. verified carbs all 100% closed at idle.. warmer it gets the worse it gets.

set idle (rpm/timin') in tha water, in gear with idle timin' screw only.. adjust linkage to allow a tiny gap between throttle cam and carb roller.. move linkage on throttle/timin' arm only!!!... this allows tha idle to be on carb idle circuit only.. don't worry with numbers.. jus make both you and tha motor happy at idle.....

 

[Texasmark]

675 RPM (+/-50) in F gear in the water, boat underway (as Duke said) seems to be Merc's sweet spot. To slow engine wants to die, to fast, shifting noisy and bad on shift mechanisms.

On Chris' comment, on my 12 year old previous engine (at the time), having run ethanol it's entire life, I was doing my carbs (for a reason) and I didn't catch the smoking gun till, after all the cleaning and soaking and wire in the holes and all, I was blasting everything good with compressed air at the end of the cleaning. Smoking gun blew out and was a tiny piece (speck) of engine fuel line, stuck down in the high speed jet on one of my 3 carbs. I wouldn't have caught it had I not finished with a good blowing out.

If you find any black specs in any of your carbs, replace all your fuel lines.

For what it's worth, my current engine is also a 2002, recently purchased. I am installing a new fuel filter and decided to check my hoses. Doing a visual, including squeezing the ends and looking for cracks, in running a cotton swab down in both ends yielded clean and intact hoses...........difference is I ran ethanol and this engine has only seen gasoline it's entire life......and I am continuing the tradition.