1966 40HP Johnson BigTwin - RDSL-28B - HOSES!

knalves

Cadet
Joined
Feb 1, 2010
Messages
9
Hi all, I have almost resurrected a '66 bigtwin that has been sitting for 8 years and all out of adjustment! I was able to get the power head free'd and did a cold compression check. Cyl #1 = 110 psi & Cyl #2 = 105 psi. Not bad for not running! I'm sure those number will come up once I get this running right.

I have searched and searched (on iBoats & the web) but, I am not able to find a vacuum hose diagram for this motor. I have the Seloc book #1300 and an original 1966 parts catalog with exploded views...

It all comes down to 2 hoses that I have no idea where they go!

#1 - Looking at the motor (carb) to the left just between the carb and starter about 1/3 from the bottom there is a cut and plugged (with a bolt) hose coming straight out off the block.

#2 - Looking at the motor to the right side - Cyl #2 is a "chewed up" pulse line coming off. the gas pump is on Cyl #1 just above it. This is a 90 nipple with a chewed hose.

Can anyone help?

Thanks!
Ken
 

tootallofwa

Petty Officer 2nd Class
Joined
Feb 20, 2010
Messages
178
Re: 1966 40HP Johnson BigTwin - RDSL-28B - HOSES!

On my 63', your cut and plugged line beneath the carb is a vacuum line to the cutout switch. (1/4 " line comes from the intake manifold then goes to the cut out switch) There is also a 5/16" line from the intake just above the other that goes to the choke diaphragm housing.

On mine the pulse line (5/16") to the fuel pump wraps over the head from the bypass cover on the lower cylinder.

I also have two water lines, One from the upper cylinder routed over the recoil starter to the top of the choke and the other from the bottom of the choke to the exhaust housing on the port side. (the tell tail)


http://i1024.photobucket.com/albums/y309/tootallofwa/CutoutSwitchsm-1.jpg
 

F_R

Supreme Mariner
Joined
Jul 7, 2006
Messages
28,226
Re: 1966 40HP Johnson BigTwin - RDSL-28B - HOSES!

1966 only has one vacuum hose. 3/16" I.D. runs from the intake manifold to the vacuum cut-out switch.

There is an oil hose running from the lower main bearing area to the upper main bearing area.

There is a steel hot air pipe running from the exhaust cover to the automatic choke.

No fuel pump pulse hose--the pump is bolted directly to the bypass cover plate.

No water hoses--they were on the old models with water heated choke. So was the vacuum hose going to the choke.
 

knalves

Cadet
Joined
Feb 1, 2010
Messages
9
Re: 1966 40HP Johnson BigTwin - RDSL-28B - HOSES!

Thanks Tootallofwa and F_R. I think you have it F_R; I am going to be working on it tonight and will post pictures of what I am referring to. After looking at it again, I think the 5/16 pulse line from #2 wraps around the back of the motor, along the left side, then to the front as some sort of equalizer for the reeds in the event of a back-fire. I could be wrong of course. But the hoses are the same size 5/16 (not that it means anything).

I do have an electric choke - not sure if it works yet.

There I go again! Thinking like an engineer. :cool:

BTW, I also have a tell-tale coming off the block! everything I've read about this motor is that they don't... But, there's a nipple with an 1/8 hose attached...

Again, I'll get pics tonight and post them shortly.
 
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