Mercury 650 carb

merc_650_72

Cadet
Joined
Feb 29, 2004
Messages
7
Hi, I just bought a 1972 Mercury 650 3 cylinder. The engine is in excellent condition and runs great but I have one concern.<br /><br />After I remove the front cosmetic cover, I can see right into the engine. There are 2 sets of flapper valves but basically I can see where the gas goes in. After I turn the engine off and trim it up, a small amount of gas comes out too. Is this normal, or am I missing another cover?<br /><br />Thanks!
 

jfholijr

Petty Officer 2nd Class
Joined
Jul 24, 2003
Messages
172
Re: Mercury 650 carb

Hello Merc_650_72 I have the same motor as yours and when you take the front cover off the cowling you are looking strait down the throat of the carbs into the reed blocks. Mine has never had any thing else to cover the carbs. Also yes when you trim it, it will leak fuel so while you are fishing and you don't have to just don't trim it or atleast not all the way. There is a tray that will catch the fuel that leaks under the carbs that will let the fuel run off around the side of the motor. If you trim it too far it the tray wont catch what leaks from the front of the carbs. What do you have your motor on, what kind/size boat do you have?
 

merc_650_72

Cadet
Joined
Feb 29, 2004
Messages
7
Re: Mercury 650 carb

Cool, someone that has the same engine as me! I just put it on a 16' PolarCraft modified V jon boat. I used to have a 1974 Mercury 500 on it, so power wise this'll be an improvement.<br /><br />The only reason I bought the 650 was because it was cheap and the starter went out on my 500. Heck for the price of a new starter, I got a whole new engine with a stainless prop!<br /><br />How long have you had yours, and what to you run it on?
 

jfholijr

Petty Officer 2nd Class
Joined
Jul 24, 2003
Messages
172
Re: Mercury 650 carb

My father in law had this thing for atleast 20 years of which the last 15 he had it layin in his garage untill I bent his arm long enough that he basically gave it to me. So I repaired it and more. It will be going on a (just wait till I'm finished) 20 foot duel console that I'm turning into a center console skiff. I know it sounds a little under powered and It will be but the boat is actually a 17 foot that has a walk around deck over the motor that brings it to 20 feet overall. The hull isn't flat bottomed but it has a very mild v and is semi trihulled at the bow. I'm most certain I will have to try a different prop or two to adjust the motor to the boat. I'm not into speed so as long as the boat will plane thats all I care about.
 

merc_650_72

Cadet
Joined
Feb 29, 2004
Messages
7
Re: Mercury 650 carb

That boat sounds pretty cool, hopefully it works out for you. I think you'll have enough power there to plane unless you load heavy.<br /><br />Good luck!
 
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