help with carb

[chesire]

could someone please tell me where I should start and what to llook for when adujsting the carb. I have a 1986 3.0 181 mercruiser I/O right now I have it about 1 and 1/2 turns from closed to the left meaning i turned it all the way to the right then turned it about 1 1/2 to the left some thing just doesn't seem right. then every time i get it i think i get get it better well and I have to start over. the book is no help say it was set a factory and not to touch <br />Ha! what do they know errrrrrrrrr thanks

 

[hondon]

Re: help with carb

First of all ,make sure your state of tune is on the money.Compression good?Dwell and timing correct?Fuel and filters clean and water free?

 

[chesire]

Re: help with carb

OK I have replaced the fuel filters. not real sure how to check timeing or dwell. Not even sure what dwell is not to mention how to check it. She was Idleing great untill i messed with it. She boggs at hi end and I started messing with the carb adujustment now I want to get it back to the proper idle so I can start working on the other problem. I just need to know what a good starting point with the screw?

 

[bertherr]

Re: help with carb

The 1-1/2 turns out is a good starting point for the air mixture screw. Make sure you are turning the air mixture screw and not the idle speed screw. My 1987 3.0 Merc I/O air mixture screw had a very small "sweet spot".<br /><br />Dwell is a measurement of the amount of rotor rotation with the points closed. You can get this close by setting the points with a thickness(feeler)gage. The motor will run much better with the points set with a dwell meter. Your valve cover should have the proper dwell setting on a plate on the starboard side.<br /><br />Set the dwell first, then set the ignition timing with a timing light. It should run like new.<br /><br />If you do not like setting points and adjusting the timing, buy and install an electronic ignition kit. You'll never have to mess with it again. Bert.

 

[chesire]

Re: help with carb

OK I did a compression check 155-60 in all cylinders. I think Ihave the carb set sounds pretty good