89 Mercruiser Bogging when throttling up.

[Jbrazington]

I have an 89 mercruiser MCM 3.0 with Alpha One outdrive. I can start it in neutral fine, and even run it up, but when I put it in gear, then throttle it up, it bogs down at around 1500-2000 rpm. I can hold the choke butterfly closed about 3/4 way and she takes off, but when I let go she bogs down again. I have adjusted the idle mixture screw out 1-1/4 turn like recommended, then adjusted up and down with no avail. I don't see any other mixture screws that I am aware of. Any ideas of where I should start?

Mercruiser MCM 3.0 Litre
181 CID
130 HP
Transom S/N 0c591342
Drive s/n 0c547644
Carb 1389-9562 3.0l 2bbl

 

[watermellonI]

Re: 89 Mercruiser Bogging when throttling up.

Welcome Aboard J
You shouldn t have to mess with that idle screw unless you ve done a carb rebuild or some other significant change to yer carb.
Do You Have a Manual?
Adjusting that mixture screw requires you to finalize yer adjustment on the water boat running and in gear.
Timing is also a factor.
When You idle this up to 1500 2000 are you on the water or on muffs?

 

[Jbrazington]

Re: 89 Mercruiser Bogging when throttling up.

When I throttle it up in gear, It is in the water under load. I am wondering if I am going to need to rebuild the carb .

 

[langford7]

Re: 89 Mercruiser Bogging when throttling up.

I know it sounds simple, but did you check your filters? I was having the same issue with my motor Saturday. I check the filters last night and they were horrible.

Good luck...

 

[Jbrazington]

Re: 89 Mercruiser Bogging when throttling up.

It has not been long since I checked the filter, but I may need to do it again. Thanks.

 

[Bondo]

Re: 89 Mercruiser Bogging when throttling up.

I can hold the choke butterfly closed about 3/4 way and she takes off, but when I let go she bogs down again.
I am wondering if I am going to need to rebuild the carb .

Ayuh,.... That would be My Guess,... Sounds like it's runnin' Lean....

 

[Jbrazington]

Re: 89 Mercruiser Bogging when throttling up.

Update: Problem is solved. I took the carb off and took it apart to inspect it. OMG! There was about 1/8" of junk in the bottom covering the power valve assembly and most of the metering ports. Cleaned it up good by soaking it in Carb Cleaner, replaced gaskets, put it back together and she runs like a champ!

 

[Bondo]

Re: 89 Mercruiser Bogging when throttling up.

Ayuh,..... Fantastic,....

I Love a story with a Happy Ending.....

 

[jeepfast99]

Re: 89 Mercruiser Bogging when throttling up.

I have an 88 3.7 merc.. and it goes ok until full throttle .. then it starts to bogg down.. the-n pick up for a second then boggs again.. its gotten worse every day..

 

[Reel-Broke]

Re: 89 Mercruiser Bogging when throttling up.

Jeep, I am having the same issue...this thread seems to be a bit old, we can move this over to my thread and see if we can sort this mess out

http://forums.iboats.com/showthread.php?t=414111