1969 merc 110 9.8 fuel line size?

[Coyote86]

Hello everyone! New to boating. Not new to tinkering(my favorite part). I have a couple questions that seem hard to get straight answers.
What size fuel line from tank to check valve?
What size fuel line from check valve to fuel pump?

I am making my own line for the check valve to fuel pump connection. I will be using BARB x 1/8 MPT. Should it be a 3/16 barb for 3/16 fuel line(harder to find)? Or 1/4 barb for 1/4 fuel line? Or does it even matter? Am I being too picky?

Any help is much appreciated!!!

 

[Scott Danforth]

its a $15 pre-made hose from tank to motor with the squeeze ball in it. other than that, I think its 5/16".

1/4" from fitting on motor to carb

 

[Coyote86]

Thank you very much for the info Scott.

 

[Scott Danforth]

here is a link. http://www.iboats.com/Moeller-Mercu...004615--session_id.942396228--view_id.1433371

you need the bayonette style.

use the current discount code is BOATING10 for 10% site wide and says exclusions apply, and that in most cases is electronics
http://www.iboats.com/Boat-Parts-and...17_SemiAnnual1

 

[Coyote86]

Thanks for the link. Is the bayonet fitting on the tank side necessary when I don't have a tank to start with? Does it have something to do with fuel flow(effect the rich/lean)? I might not even do a bayonet at the motor side either. The bayonet on the motor seems to be missing some parts. Most photos I see of the bayonets have a needle valve inside. Mine does not. So it either needs replacing $$$ or rigged to use something newer and more readily available.

 

[Scott Danforth]

the bayonet connection is to allow the motor to be disconnected and the tank swapped. the 9.8 weights only 67# and has a carrying handle on it. there is a spring loaded safety valve to prevent fuel spill when you disconnect the line

personally I wouldnt hook up a small motor without some sort of quick disconnect at both the tank and the motor. no, technically if you never remove the motor or never change tanks, you wouldnt need them. however I have been boating long enough with small outboards to know that you burn thru fuel, and its only seconds to switch the line from one tank to another. many times I have done it while still on plane with only slowing down a few mph

 

[Coyote86]

That makes a lot of sense. I was in a rush and I must have misrepresented my question. Is a bayonet specifically required or is there a different type worth using? I still want quick disconnects. I don't mind modifying the one motor side.

 

[Scott Danforth]

Merc stayed with the bayonets until the late 90's thats over 50 years with the same style connector. they now have one similar to the Johny-rudes

its your choice. do not get the plastic bayonets though, they leak

 

[Chinewalker]

The 1969 9.8hp will use a non-standard small fuel fitting from Mercury. I have not found an aftermarket version for it. They can be had new, Mercury part number 30635T3. Can be found for $25-$30 online. The smaller male fitting on the motor side didn't have the check valve pin like the larger fittings did.