90hp head scratcher

dutch420

Petty Officer 3rd Class
Joined
Sep 16, 2012
Messages
84
Hey everyone picked up a new to me boat on thursday.
Motor is a 1990 90hp mariner
Have a few questions. Frst guy could not keep it idleing. So i played with a adjustment screw where they all connect on the motor seems to idle now hope i turned the right part.lol. Not sure what that part is called sorry
I also noticed when on the muffs i have water coming from the shift linkage.
Anyideas.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Spend a few bucks and get a service manual. Money well spent. Go to the top of the page and in the Boat parts & Accessories, in the querry box plug in Seloc Manuals. You can rent time on the www or buy a physical manual. I used the online and it was fast and worked for me.

The carb to engine timing sinc and link setup is a little tricky so you need the manual. On what screw you turned, who knows. Idle on these engines is not controlled by the carb butterfly, rather changes in engine timing and the screw is just above where the remote controls mount and adjusts that linkage. The screw on the side of each carb is the low speed needle which affects hole shot.
 

dutch420

Petty Officer 3rd Class
Joined
Sep 16, 2012
Messages
84
Hi texasmark
Ya i will definitely be investing in a manual. From what i understand from what ur telling me i adjusted the timing then.. seems to run better but have to put in in the water to know for sure. I did turn air fuel in and counted how many turns in on each carb. And reset them . Bottom carb had brownish chunky crap in it.lol. so i pulled and cleaned it as well as replaced the fuel lines. I found the roller that opens the carb butterflys was not in uts linkage properly and fixed that.. had to adjust that timing screw a good ways to make it start and idle decent.
 

Texasmark

Supreme Mariner
Joined
Dec 20, 2005
Messages
14,544
Hi texasmark
Ya i will definitely be investing in a manual. From what i understand from what ur telling me i adjusted the timing then.. seems to run better but have to put in in the water to know for sure. I did turn air fuel in and counted how many turns in on each carb. And reset them . Bottom carb had brownish chunky crap in it.lol. so i pulled and cleaned it as well as replaced the fuel lines. I found the roller that opens the carb butterflys was not in uts linkage properly and fixed that.. had to adjust that timing screw a good ways to make it start and idle decent.
Not standing next to you when you did what you just said, but the "link and sink" aka setting up the carb butterflies to all operate in sync with each other and then setting that "sync" linked to the timing changes from about 4 BTDC at idle to about 20 at WOT is a procedure explained in the manual. Not intuitively obvious to the unlearned. If you got it right I'd call it"blind luck and superstition". Also, if any of those little plastic parts that hook up all the linkage are broken or slippy, it will make it hard to get it right. Good luck
 
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