'97 ALPHA 1 3.0L Black smoke while idling...

[WALLEYE DIVER]

My buddy has a '97 175 searay with alpha 1 3.0Liter/LX mercruiser that has been smoking while it idles...It runs good full throttle, just smokes bad black smoke at idle.

any ideas where to start looking?

does anybody know if this motor has a mixture screw on the carb to adjust the idle mixture to lean it out?

 

[Blk-n-Blu]

Re: '97 ALPHA 1 3.0L Black smoke while idling...

Walleye, Sounds like its running real rich. I would start with the choke adjustment if it has one???Carbed???:'(

 

[Reel Poor]

Re: '97 ALPHA 1 3.0L Black smoke while idling...

It sounds like the choke flap is not opening as the engine reaches normal operating temperature. Remove the flame arrestor and check choke flap for proper operation. Also make sure flame arrestor is clean and clear.

 

[WALLEYE DIVER]

Re: '97 ALPHA 1 3.0L Black smoke while idling...

Anybody happen to have a diagram of the carb for that motor?

its been raining last couple days, as soon as it clears up I am going to to help my buddy see if we can fix it... other wise its off to the shop. the only problem is, the soonest we can get it in somewhere is about 3 weeks. It would be nice if we could just figure it out, and get back to boatin'.

 

[Blk-n-Blu]

Re: '97 ALPHA 1 3.0L Black smoke while idling...

Walleye, have a look here.

http://www.boatfix.com/merc/Techbk/94/94hg5b.pdf
hope it helps (assuming you have a two barrel mercarb
and here if its the four barrel
http://www.boatfix.com/merc/Techbk/94/94hg5c.pdf

 

[Don S]

Re: '97 ALPHA 1 3.0L Black smoke while idling...

B&B, those are for a 94, not his 97 Vintage.
Anyways, here is a link to the full Mercruiser service manual for the 3.0L engine.

http://www.boatfix.com/merc/Servmanl/13/13covr2.pdf

Those carbs have electric chokes, and I replace at least 4 a year that won't open the choke anymore.
To answer your other question, yes it has a screw for idle mixture but you won't be able to adjust out a inop choke or even a defective fuel pump could be dumping fuel into your carb. Check the clear hose that goes from the fuel pump to the carb. If there is any gas in it, replace the fuel pump.

 

[imported_andrew smith]

Re: '97 ALPHA 1 3.0L Black smoke while idling...

Don, do you have a link to a Mercruiser service manual for a 2005 3.0L with TKS carburetor? Many thanks, your information on this forum is much appreciated. (sorry for jacking this post....)