fuel pump

[HerbS 6]

I have a 416-8 that's not sucking gas.  I've replaced the pump and the hoses.  The gas comes with a hand pump, but there's no suction coming from the engine.  The suction hose may have come loose from the engine but I can't get the engine casing off to check.  What's the trick to getting the casing off.  Thanks. 

[kpinnc 14,599]

Assuming you're talking about an Onan P216, there should be just enough slack in the pulse line to see if it's attached to the back side of the pump without removing the tins. Simply remove the screws holding the pump on and gently pull it out enough to see the hose attached.

 

That being said, it's always good to periodically remove the shrouds and check the cylinder cooling fins for debris. Onans are notorious for piling dirt and clippings on the inside of the fins, which leads to catastrophic failures due to overheating. 

[Handy Don 14,019]

On 5/7/2023 at 2:59 PM, HerbS said:

What's the trick to getting the casing off.  Thanks. 

Yep, these can be tricky.

Focus on the outer housing only (i.e. NOT the ones that are over the two cylinder heads).

 

You already suspect the pump pulse hose, but before starting on tins, CONFIRM that it is disconnected as @kpinnc suggested.

 

If it is NOT disconnected and you decide to proceed to clean the engine fins, then disconnect the pulse line at the pump. 

Once it’s disconnected, then most of the bolts are obvious, but...

 

There are two bolts upward through holes in the engine plate.

With the air cleaner completely off and a rag stuffed into the carb throat to keep dust/debris out, loosen/remove the coil as there is a bolt underneath it. Note the wire positions for reassembly. Be ready to grab the bolt so it doesn’t fall into the fins below (same for reassembly).

You may want to detach the wires from the voltage regulator, again noting wire positions for reassembly, if it is in the way.

 

As noted above, the pulse line (which is standard ¼” heavy wall fuel line) should have about one inch sticking out of the tins--just enough to access the hose clamp. When I reinstall new, I leave two or three inches and then trim before connecting the pump. I’ve also stuck a piece of ¼” dowel into the hose to help me line it up with the hole in the tins.

 

Also note, that several of the bolts holding the tins are in threaded holes in the aluminum parts of the engine. Use care and caution when removing them since extracting a broken bolt from an aluminum part is a bunch of pain to be avoided if possible.

Edited May 9, 2023 by Handy Don

[Horse Newbie 7,395]

When you remove bolts from fuel pump and pull it away from the engine tin, see if you feel some resistance… if you do the pulse line is probably still hooked to the engine. If you don’t feel any resistance, then the pulse line may be securely attached to the pump, but not the engine…