bigtwin will it be ok? your thoughts

[kodibass]

I have a rudy bigtwin 1954 25 hp, I want to put a carb from a 1957 rudy 35 bigtwin on the 25, here's why I cannot find the part number for the glass bow which is needed to make this carb usable, the 35 does not have a glass bowl as part of it's carburetor but it mounts to the block. so do you think the 35 carb will fit/run ok??
lmk thanks kb

 

[freddyray21]

Re: bigtwin will it be ok? your thoughts

I think the float bowl from the 35 will screw right onto the 25 carb. Problem solved. Then just use an inline gas filter.

 

[jbjennings]

Re: bigtwin will it be ok? your thoughts

FreddyRay,
Do you think that the 35 carb will allow the 25hp to make more hp, or just drink more gas? I'm curious because I have a '56 30 I wouldn't mind putting a '57 35hp carb on if it would benefit the hp. Didn't mean to hijack, but I believe the question pertains to his motor as well. Basically, I'm wondering why he wants to use the 35carb on a 25 motor. Same stroke and displacement?
Thanks,
JBj

 

[kodibass]

Re: bigtwin will it be ok? your thoughts

I want to use the 35 because I don't have a glass bowl, the 35hp glass bowl was gone when I got the engine, The bowl holder is there but not the bowl, the 25 hp must have a bowl as it is part of the carburetor, I just want the engine to be usable. so if the carb for the 35 will work? I can use any in-line filter. I plan on trying it soon and i'll see what happens.

 

[Chinewalker]

Re: bigtwin will it be ok? your thoughts

Sure isn't going to hurt to try. If it doesn't work, I may have a 25 carb for you...

 

[1946Zephyr]

Re: bigtwin will it be ok? your thoughts

jbjennings, The 25 and the 30 are the same displacement (35.7 cubes) and the 35 was upped to 40.5 cubes in '57. If I'm not mistaken, the 25 and 30 have the sediment bowl integrated into the carb, whereas the 35's and 40's had it integrated externally, or in the fuel pump assembly, on those models that were equipped.

 

[Mas]

Re: bigtwin will it be ok? your thoughts

Try finding the glass bowl at sea-way.com in seattle. Or post a want ad on the AMOCI.org site (Antique Outboarders free classifieds).
I'm not sure if the '57s needle valves will line up through the air silencer or the cowling. Also, the sediment bowl is very small...I believe much smaller than the float bowl. I do not know these ideas for certain, but just what's on my mind.

Mas

 

[Mas]

Re: bigtwin will it be ok? your thoughts

Also, the carb linkages are probably different.

Mas

 

[freddyray21]

Re: bigtwin will it be ok? your thoughts

the glass bowls can be bought. I have a couple. but like I said if you take the bottom of the 35 carb and put in on the 25 carb you do away with the need for the bowl.

 

[F_R]

Re: bigtwin will it be ok? your thoughts

The 25hp bowl goes on the carburetor body, not the float bowl.

The part number for the 25hp bowl is 302676. www.marineengine.com has more than 10 of them in stock.

The 35hp motor is 40.5 cubic inches. The 25hp motor is only 35.7 cubic inches. Carburetors are engineered to match the CID of the engine they are to be used on (Air flow through the venturi is different). Putting a larger carburetor on often causes a performance problem, like bogging at mid throttle, poor acceleration, low torque under heavy load, etc, etc.

I say get a new glass bowl for the 25 and be done with it.

 

[kodibass]

Re: bigtwin will it be ok? your thoughts

thanks F_R & everyone also, just ordered 2, I found this motor in a heap, but amazingly it all seems there and nothing besides the transom clamps seem froze up, I hope to have it going soon>
kb

 

[kfa4303]

Re: bigtwin will it be ok? your thoughts

Glad you got the parts you needed kodibass. For future reference, ebay and amazon also carry a lot more of the common bits and pieces for these old OMC motors than you might think. Here is a link to a list of manuals for all the 25hp made in '55. Click on the same model as your motor. A lot of the diagrams and part numbers should be the same for your '54.

http://www.marineengine.com/parts/johnson-evinrude-parts.php?year=1955&hp=25

http://www.duckworksmagazine.com/04/s/columns/max/24/index.cfm