fuel pump install...?

suzuki40

Petty Officer 1st Class
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Feb 14, 2003
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278
I have a 4 hp Johnson seahorse Model# 4w79d<br />The fuel tank is built in the top of the engine and holds about a quart of gas I would guess? I am interested in installing a fuel pump on this motor so I can run a 3 gallon tank for it. Im always having to refill the small internal tank every time I turn around. Anyone have any information on doing this? Is there a fuel pump that is made for this motor? I have seen this motor on other boats without an internal tank.<br /> Thanks,<br />Suzuki40
 

OBJ

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Dec 27, 2002
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10,161
Re: fuel pump install...?

Finding a fuel pump is the easy part. Finding a place on the block to mount it so the press/vac of the block would operate it may be a poser. You could use a fuel pump from a 4.5, of later years, but you need a place to mount it. Not familiar with the block so this is about as much as I can add.<br /><br />Maybe one of the other guys can help more or take a look at one that has a pump and get some ID's.
 

suzuki40

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Feb 14, 2003
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278
Re: fuel pump install...?

Thanks for the response OBJ, I guess a new manual would answer a few of my questions? I think this motor came with a fuel pump on some models? I start diggin'. Thanks again.<br /> Suzuki40
 

Xcusme

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Apr 21, 2003
Messages
2,888
Re: fuel pump install...?

Suzuki40, I have the manuals for the 71' and 76' 4HP. I looked at both powerheads and I see that both the integrated tank and aux fuel pump are shown. In the integral tank model, there is a pulse hose going from the side of the powerhead to the carb. This pulse hose provides a pulse of pressure to an internal diaphragm inside of the carb to give the fuel some pressure to enter the carb and operate the carb float.<br /><br />The list shows a fuel pump of 389046 can be added to replace the pulse hose. I'm sure you will have to 'cap off' the old pulse line input at the carb. You will need to buy and install the 'fuel connector assembly' (where the external tank hose line will connect to the motor). A length of fuel hose from this fitting will go to the input of the new fuel pump. The output of the new pump will connect to the carb at the same location as your original tank.<br /><br />As you may have gathered, they show 2 lower carb. bodies, one for a built-in tank, the other for an external pump, like you want. <br /><br />Just a word of caution...you just knew it was coming right?? Use new fuel lines thru out the new retrofit along with new clamps. Check any new fuel line routing for points of abrasion and adjust for proper clearances as needed. We sure don't want you to coming back saying the motor suddenly made the 'Whomping Sound' <br /><br />Good luck, and keep us posted on your progress. :p
 

OBJ

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Dec 27, 2002
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10,161
Re: fuel pump install...?

Thanks X..... :D
 

suzuki40

Petty Officer 1st Class
Joined
Feb 14, 2003
Messages
278
Re: fuel pump install...?

Hey, Thanks a million X. I am on the job as of now with this new info. I'll let ya'll know how it all turns out when it's finished. Thanks to all that responded.<br /><br />Suzuki40
 
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