'55 Johnson 25 Hp Fuel Pump Conversion Questions

[Shakedownscott]

Thanks to a lot of great info on this site and help from members, I think I am ready to try this conversion.

I am updating my ouboard to an OEM fuel pump p/n 438556. From what I have found this pump is used on a bunch of 25-40 Hp johnson motors starting in '69. This pump bolts to the bypass cover and uses a thick gasket p/n 303615. Does this gasket require any sealant, if so what type?



I also got a new bypass cover p/n 313871. This cover has two mounting holes for the fuel pump and a threaded hole that lines up with the center hole in the pump. I am assuming that the threades in the center hole would be used in a different application, is that correct?



My plan is to replace the upper bypass cover with this set up. Does the bypass cover gasket require any sealant?



I am going to remove the fitting for the pressure line and replace this with a bolt to block it.

Am I missing any thing else with this conversion?

Thanks

 

[Daviet]

Re: '55 Johnson 25 Hp Fuel Pump Conversion Questions

No sealant on the gaskets. Don't worry about the threads in the bypass cover center hole. Sounds like you are on the right track.

 

[1946Zephyr]

Re: '55 Johnson 25 Hp Fuel Pump Conversion Questions

Yep, you're lookin good. Bypass cover from a 28hp and fuel pump makes it an easy conversion. As far as blocking off the nipple that fed the pressure tank, I would not use a bolt, because they are a different thread. I would take the nipple in to Nappa and get a small plug that matches the same thread.

 

[Shakedownscott]

Re: '55 Johnson 25 Hp Fuel Pump Conversion Questions

Great thanks. I can't wait to try this out and see if it works.

 

[Shakedownscott]

Re: '55 Johnson 25 Hp Fuel Pump Conversion Questions

Looks like the bypass cover is not the same from a 60's 28 Hp and a '55 25 Hp. It is a different size altogether. The cover is too big to fit into the opening. I looked up the gasket p/n and they are not the same between models. Oh well, I wish I had checked that before buying the parts.

Any ideas on how to adapt this pump to this motor?