1973 merc 200

[Riverrat47274]

Re: 1973 merc 200

Or atleast do check of float level.thank's!

 

[little.boat]

Re: 1973 merc 200

If you just got this motor I'd defiantly clean and rebuild the carbs. Don't want to blow the power head due to dirt carbs.

 

[oldman570]

Re: 1973 merc 200

Or atleast do check of float level.thank's!

A good carb cleaning and the float level setting checked is good advise. Make sure that you replace the fuel pump diaframs as well. If the drain plug for the LU is stuck, you might use a small punch or chisel on the outside conner of the slot and at a angle, to tap it lose. Or try a large washer that will fit the slot better, as some plugs have a concave to them much as you find on a $.25 . Now would be a good time to replace the drain plug and the gasket. You may be able to get a new drain plug that has a Allen head for a replacement that will be a better setup for easy removal next time. JMO
Oldman570

 

[Riverrat47274]

Re: 1973 merc 200

Checked fuel line.primer bulb is staying firm and getting good flow of gas to carb.idle mixture screw is set 1 1/2 turns out.

 

[Riverrat47274]

Re: 1973 merc 200

Took carb off today.every thing looked good and clean except float was not set right(set at 7/8") instead of 1/4" and fuel pump screen had a bunch of stuff in it.so i decided to order rebuild kit and i'll redo carb.will update once kit comes in.thank's for all the advice!!!!

 

[Riverrat47274]

Re: 1973 merc 200

I have a question about the float movement.float does not move up and down unless fuel pushes it up.other motor's ive had,the float would move if you flipped carb upside down then back over.does this sound right?

 

[Riverrat47274]

Re: 1973 merc 200

Got float set,but now ive got fuel coming out the front of the carb and motor still wont start.must be flooding now.im about to give up and just buy a new motor.

 

[jbjennings]

Re: 1973 merc 200

If fuel is pouring out the front of the carb, then the float is not set correctly or there are other problems. Do you have 2 little flat metal arms under the top of the float bowl that the float rises and pushes on to close the float valve? If so, there may be a slight crack in the float, or the arms may be bent. I wouldn't give up on that motor if it starts and runs so well when warm. Where are you located---maybe one of the folks on this site is close by?
JBJ

 

[Riverrat47274]

Re: 1973 merc 200

according to my seloc manual,with carb upside down the top of the float(actually bottom)should be 1/4" from carb.i had to bend float tab to achive this setting.i live in southern indiana.motor will fire up and run great if i prime motor by spraying premixed gas into carb.can shut motor off and restart no problem.but if motor sit's for 30 minutes or more i have to prime again.almost like its not getting enough gas to cylinders.this confusses me.if motor was not getting enough gas then it should spit and sputter while running at some point.help please!!!

 

[Riverrat47274]

Re: 1973 merc 200

Could the timing be off to wear the carb is not opening up enough to allow the right amount of fuel to get to the cylinders?

 

[jbjennings]

Re: 1973 merc 200

No, you should crank it with the throttle open slightly. It should have a throttle stop to prevent wide open throttle starts when in neutral. You may have wear at the throttle shaft in the carburetor if it has one, allowing it to suck too much air and not enough fuel, or a vacuum leak around the intake, carb, etc. There's so many things that can cause a problem like this, it's hard to help you without looking at it. Leaking crankshaft seals would also cause it. But NOT likely timing as far as I know.
Wish I could help more,
JBJ

 

[Riverrat47274]

Re: 1973 merc 200

Ok thanks bj

 

[Gibbles]

Re: 1973 merc 200

Fuel mixture settings can also affect a cold start.

Richen it by a quarter turn at a time keeping track where it was at.

 

[MH Hawker]

Re: 1973 merc 200

Its been my experience that merc`s need to be set a bit rich for easy starting, slowly open the air mixture screw over time till you fine the sweet spot for cold starts, it normally shouldn't take over 3 pulls.

 

[Riverrat47274]

Re: 1973 merc 200

I got to do some more inspecting and found that the fuel line from fuel connector to carb was sucking air.i fixed that and now she fires right up.thanks for all the help!!!

 

[jbjennings]

Re: 1973 merc 200

Great! I'm glad you posted the solution. I love those 70's merc 200's when they're "right".