85 50 hp mariner running bad on 16' boat

[srussell28]

Hello,<br />I've gotten a lot of help from you guys here, my boat still is not right. I'm only getting 8 mph. I get spark to all the plugs, ball is hard, new gas tank, plugs, rebuilt carbs, new power back last year, new water pump, 125 psi on all 4 cyl's. I Have found that if i cover the carb on the top with my hand there is no change, if I cover the bottom with my hand i will almost cut off( I know this is what should happen) I took the top one out, below the idle mixture screw there is another screw with a hole in it, this was turn out. The carb on the bottom is turn all the way in. what is this? Could this be my problem? Please let me know what else to do or check. Carbs are stamped 4/85 top wma 3-1 and bottom wma 3-3. Thanks

 

[Laotzu]

Re: 85 50 hp mariner running bad on 16' boat

My manual has a picture of your carb and it looks like that screw might be a vent jet. Since that carb provides fuel for two Cyl. it is probable that your running on 2 cyl. Same symtoms I had when one of the carbs on my'91 50hp was plugged with gunk.<br /><br />The only thing it says about the vent jet is to tighten to 14 in.lb., no adjustment mentioned. I'd give the carb an immersion bath in carb cleaner and blow dry with commpressed air. Also make sure the float isn't absorbing fuel and all the jets look ok and clean.<br /><br />Jerry