Johnson V4 Fuel pump swap

[stevetedder]

Ok so Ive come to the conclusion the VRO fuel pump is bad. Since the engine is already set up for premix fuel can I skip out on the $400 VRO pump and somehow install a regular Johnson outboard fuel pump($100) from a older motor? If so, where does the vacuum for the pump come from? How does it mount up? Any help is appreciated.

 

[SparkieBoat]

Re: Johnson V4 Fuel pump swap

yes you can order a new pump for a 112 special motor, it will work for your motor..if you can find one to look at you will see where it should bolt up.

 

[TombigbeeMan]

Re: Johnson V4 Fuel pump swap

For your 84 90 I would think your engine probably has a mounting spot for a manual pump already there. Once you completly remove your VRO you will see two threaded holes on and a bolt or screw inbetween the holes on the side of the block right above your pulse limiter...(I'm writing this out of memory from last year when I done mine)... Did have to figure out rerouting the fuel lines but other than that it was pretty straight forward. No need for a vacume line, you will put a plug in the block where the pulse limiter was and then take out the bolt or screw between the two threaded holes..the threaded holes are used to bolt the fuel pump up to the block.....hope I havn't confused you

 

[stevetedder]

Re: Johnson V4 Fuel pump swap

Success!! It can be done,It actually mounted right on the intake.from the same hole as the VRO pulse line. After removing the nipple that was there I just bolted on the new pump with a gasket and run the fuel lines. Runs like a champ on muffs. Weather permitting Ill take it out to the lake tomorrow. Thanks to all who replied

 

[stevetedder]

Re: Johnson V4 Fuel pump swap

 

[stevetedder]

Re: Johnson V4 Fuel pump swap

Took a sec to figure out how to upload images here could be a little more user friendly.....
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[DargelJohn]

Re: Johnson V4 Fuel pump swap

Don't know if it matters, but I think you have it mounted upside down. There is a weep hole, in the fuel pump body, that leaks fuel in case of diaphram failure. May effect how that works.

The inlet and outlet fuel lines should point downward. Attached pic is of my
'96 88SPL which is a similar motor.

 

[stevetedder]

Re: Johnson V4 Fuel pump swap

Wow your right!! I didnt know there was a difference,runs great though I wonder what happend if diaphram fails and its upside down this way?

 

[DargelJohn]

Re: Johnson V4 Fuel pump swap

The weep hole should be near the bottom of the pump. So, If the pump is upside down, then the entire inside cavity will have to fill with fuel before it comes out the hole, letting you know there is a problem.

If it were me, I would turn it around.

 

[stevetedder]

Re: Johnson V4 Fuel pump swap

Glad you seen that, was getting ready to take it out, should only take a few min to do it, thanx.

 

[DargelJohn]

Re: Johnson V4 Fuel pump swap

Glad you seen that, was getting ready to take it out, should only take a few min to do it, thanx.

Steve, One other thing I noticed, in your pics, was the fuel filter. Fuel filter should be placed somewhere between the gas tank and the primer bulb.

Fuel Tank>>>Fuel Filter>>>Primer Bulb>>>Engine

Nice job figuring out that you could use a manual fuel pump. Like you said, big cost savings.

 

[stevetedder]

Re: Johnson V4 Fuel pump swap

Thanks for the kudos on the fuel pump, I did invert it today. Hoses were a little awkward to get on but not pinched or anything, still runs great. The filter you see in the pic is #2 formerly number 3 out of 5. I think the previous owner might have been a little paranoid. I may still run 3 myself though.
1. glass type strainer
2. fuel water seperator ( both before the primer bulb)
3. regular paper type like you see in the pic (either before the hood or just under it before the pump) Overkill?

Im fairly knowledgeable of autos but 2 stroke engines are relatively new to me so I am definately open to sugestions and constructive criticism.