110 merc carb help !!!!

[jaylo600]

does any one no what the little black plastic venturi looking part is inside the carb throat ? Mine is broken off on one of the side wing parts and I was wondering is it possible to run it without ??? I tried the merc parts online microfishe but it's closed.

 

[emckelvy]

Re: 110 merc carb help !!!!

It not only looks like a venturi, it IS one!!!! How 'bout that!

The venturi modifies airflow thru the carb and I expect it might not idle real good without it, due to diminished "signal" to the fuel side of the carb.

Lack of venturi at higher speeds may not affect operation as much but I bet it'll still run a little on the "wacky" side. Can't say that I ever ran one with the venturi missing.

On a side note, both 7.5's and 9.8's have carb venturi's, but the 7.5's is larger in diameter which restricts airflow which (in addition to different porting in the block) drops HP from the 9.8. Unfortunately you couldn't just swap a 9.8 venturi into a 7.5 and turn it into a 9.8, because of the different porting. But the displacement is the same, as are the crankshaft & pistons.

So, when you do find a part, be sure it's for the 9.8 not 7.5 as you wouldn't be happy with the results.

Here's a good Wiki read on carb basics including an excellent description of how a venturi works: http://en.wikipedia.org/wiki/Carburetor

BTW I wonder if it might just stay in place with only one of the wings busted. I suppose you could try and dislodge it from its position and see what happens.

There's Venturi 101 for ya, and probl a lot more than you bargained for!.....ed

 

[jaylo600]

Re: 110 merc carb help !!!!

Hey I love as much info as I can get and thanks alot for the response. Your guess is right, I was able to still use the venturi as the main pilot does most of the work holding it in place. The Wiki link is very informative as well. I have repaired engines of all different types in my days and I learn something new almost everytime I attempt another one thanks to helpfull people such as yourself ! Thanks again

 

[dajohnson53]

Re: 110 merc carb help !!!!

Hey I love as much info as I can get and thanks alot for the response. Your guess is right, I was able to still use the venturi as the main pilot does most of the work holding it in place. The Wiki link is very informative as well. I have repaired engines of all different types in my days and I learn something new almost everytime I attempt another one thanks to helpfull people such as yourself ! Thanks again

I broke the venturi the first time I cleaned the carb on my '74 merc 110. I didn't use a rebuild kit, just a gasket kit that time. I just used JB weld to repair it. I made sure it was really, really clean and oil free and then dressed it carefully with a dremel once it dried. It worked fine for a couple years. Later, I decided to do a rebuild and bought a rebuild kit. I THINK it had a new venturi in it. Otherwise, I found the venturi somewhere - they are available. I can't really remember if it was in the rebuild kit or separate. One source for parts that's pretty good is oldmercs.com, you might check the website and/or give a call to them.