1989 416-8 onan help

[Matt Polk 27]

I have a 416-8 with the onan. It doesn’t run smooth and it doesn’t have the factory fuel system setup. Somebody had put a aftermarket fuel pump etc. I want to take it back to factory but I have a couple of questions. 1. Where does the factory pump mount? 2. I noticed there is 2 inlets and 2 outlets on the factory style pump. Where do they go? I know one is fuel tank, then one goes to the carb, and one is vacuum? What’s the 4th outlet for? This is the pump I found online. Any help or pictures of the setup would be great! 

[cleat 4,936]

I don't know why they have the 4 barbed fittings on the top and bottom, only 2 are used.

 

Bottom left and top right are used.

 

Top left gets that cap put on it that is shown in the picture and a clamp put on it.

 

Bottom left is fuel inlet, top right is outlet.

 

Bottom right is moulded without a hole so just ignore that one.

 

Vacuum connects to the rear facing nipple.

 

Edited March 26, 2020 by cleat

[WHX?? 46,682]

Note the nipples that are capped as they are not used. Ther is only in, out and pulse. Pulse line is on the back. It would have been mounted on the fan shroud. Left rear side of engine you should see mounting holes and a hole for the pulse line to block. 

A few guys ditch this pump and go to electric. I have never had issues with factory but would consider it.

 

Cleat's a faster typer! 

You can see it on the upper rear part of shroud on this 520. Those pumps can be had for 20 clams on fleabay. 

Edited March 26, 2020 by WHX24

[Matt Polk 27]

Thanks guys! That helps a lot! 

[lynnmor 6,762]

Since the problem is that it doesn't run smooth, be sure that the pulse hose is on the back and doesn't leak at each end.

 

If that checks out, I doubt that the fuel pump is the issue.  The most common problem for rough running is dirt in the carburetor.  There are many other things that it could be, but I always start with a compression check rather than chase my tail trying things on a sick engine.