1956 30 hp carb question

[R. Bushie]

I am re-building the carb from my 1956 30 hp RD-18 Johnson and have noted a concern while cleaning and inspecting. Let me try to explain....looking at the top of the carb main body is the slow speed needle passage tube. At a 90 degree angle there is a cross passage that seems to pass through the slow speed tube (just above the throttle shaft).This cross passage was identified on another models parts breakdown as 'fuel passage" At the throttle shaft arm side there is a 1/8 " machined hole that is at the end of the said fuel passage. Is this proper or should this hole be plugged? The carb on my 30 hp is slightly different than the one shown in the RDE-18 parts breakdown...mine does not have the plug located on the choke lever side identified as #36 of the parts catalog. The only number I can find on the casting ia a number that is hard to read but may be # 377385. Should the hole be plugged or left open...info please ( hope I've explained well enough) thanks

 

[daveswaves]

Re: 1956 30 hp carb question

After reading your post I looked at a carb I just took off a 57 evinrude 35 hp which should be the same carb, the passage in question has an aluminum plug (standard domed plug that you press in and dent to expand and seal). Someone must have removed your plug to clean the fuel passage.

 

[R. Bushie]

Re: 1956 30 hp carb question

Hi daveswaves, I have a 58 35 hp as well and in looking at this one, there is a larger 3/8 " aluminum plug situated under the manual choke arm as you explain on yours, my 30 hp does not have that. The hole in question on my 30 is on the other side (above the throttle arm) and is a small 1/8 " drilled hole that enters the fuel passage. This motor I just received and am rebuilding, I know that it ran before I got it, but I'm not sure what's up with this hole, if it should be plugged or not. My parts catalog does not show this item, but a parts catalog from a later engine shows a small plug called a "plug fuel passage" that the exploded view indicates would go there, probably a brass slug as I've noted installed at other locations on my 30 hp carb. Good to hear from a fellow "Ontarioite"

 

[daveswaves]

Re: 1956 30 hp carb question

Yup, I have a 1/8 brass plug in mine, the plug is at the end of the passage and if you are looking at the top of the carb the passage runs 45 degrees to the low speed needle chamber. The fuel passage in question runs to the starboard side of the carb, down the side and enters the fuel bowl at the bottom, there should also be a removeable threaded brass plug at the fuel bowl end. Hole should be plugged,

 

[Ed L]

Re: 1956 30 hp carb question

You are in the same vintage as my engine. I have an RD-14. Which carburetor kit does it take? After I get it, I may be carefully reading this thread for help. Thanks.

 

[R. Bushie]

Re: 1956 30 hp carb question

Hi Ed L, your RD-14 is a 1953 25 hp and it takes the same carb kit as mine. Sierra kit # 18-7024. I have a 1955 25 hp as well as my 56 30 hp, the 25 is a great old engine, they don't make em like that these days. But the carb on my 25 is slightly different in that it does not have the 1/8 " hole as described so it doesn't answer my original question....good luck on the rebuild

 

[Ed L]

Re: 1956 30 hp carb question

I thank you.

 

[R. Bushie]

Re: 1956 30 hp carb question

Still looking for info on the carb issue. If a picture would help I can send one...not sure how to post a pic on this site. My comment that the passage passes through the slow seed passage tube isn't quite true, on re-examination it does pass below but does not enter the slow speed passage tube. Would this just be a vent passage?

 

[Paul Moir]

Re: 1956 30 hp carb question

EMail the pic to me and I'll gladly post it. paul.moir@ns.sympatico.ca<br /><br />Since they changed the carb so much, I think a picture would really help to make sure we're all on the same page.

 

[Paul Moir]

Re: 1956 30 hp carb question

Here it is:<br />

<br /> <br />It doesn't match any of the carbs I've got kicking around.

 

[Paul Moir]

Re: 1956 30 hp carb question

^BUMP^<br /><br />It sure looks like the idle needle valve's fuel supply, but I don't see a vent anywhere else either and a carb's got to have a vent...

 

[55Crestliner]

Re: 1956 30 hp carb question

The carb on my '57 18 horse has a small hole like you describe, it is not plugged. Motor is running great, has been for almost a year, I think the hole is supposed to be there - well, at least on mine - I'd bet for yours too.<br /><br />My suggestion? Rebuild the carb, and start it up. If it runs right, leave it. If it's a problem, plug it, but make sure you can get your plug out easy enough if that really wasn't the fix.<br /><br />That's what my 1 year of outboard experience would have me do.