Ideas on carb replacement failure

[Rivets]

I hope you’ll let us know when you get it running.

 

[sgkent]

a little hard to get the new dry carb to suck fuel, but once it was going it ran nice and strong. I'll let it sit a few days and see how it starts then. Has a random rattle under load at 3400 but none with no load at 3600. Could be the pump or who knows. It probably hasn't had this much compression in a long time. Could be the starter release too clanking a little because I oiled that so it would have a bit more drag than the dry ball bearings. If so that should work out quickly. Could also be the exhaust valve. The stem was carboned up and I cleaned that up.Lots of guide wear so I am sure it is moving around a little. DIdn't sound serious, came and went as I opened the pressure wand.

 

[Ericcburson]

Have a pressure washer, 20 years old. Briggs 4 hp quattro engine. At the base of the carb are two gaskets/diaphrams where it sits on the fuel tank. The engine is very hard starting. Once it gets going it is fine. The primer bulb will fill will fuel in two or three pumps. In late October 2021 I once again replaced those gaskets/diaphragms and the engine was fairly easy to start. Now it is late Feb 2022, new fuel and once again it is hard to start. Air filter is a green universal one instead of the factory one. After pulling maybe 20 times I removed the air cleaner and tried it again. It started on the second or third pull. Does anyone have any experience with the engines that have the carb on the tank, where they are able to easy start their engine, and keep it that way for years without having to replace the carb etc once a year or two? Also does anyone have any experience where some of the universal air filters are too restrictive and they are the cause of the hard starting?

It is this style carb and tank, and filter. Photos are from the Internet. The filter in this image is the Briggs factory filter. The universal ones are a green dense foam.

Ive found that some carburetors actually fit nicely together backwards or 180’ off.

 

[sgkent]

Ive found that some carburetors actually fit nicely together backwards or 180’ off.

physically impossible with this one

 

[sgkent]

Success and failure. The pressure washer runs fine. Really strong and steady. Starting is another story. It has been sitting about 5 or 6 days. It has a new factory carb. When I press the bulb to prime it there is no resistance. If I press six to ten times quickly it will get hard, then 3 presses and the engine will start on the first pull. If I try to start it before the bulb gets hard, you can pull and prime all you want, but it won't start. I would think that the fuel should not bleed down from the primer bulb but what do I know.

 

[Scrubcadet10]

these carbs are prone to warpage along the base where they meet the tank. 2 gaskets then the diaphragm *might*work... im not sure.

 

[sgkent]

carb and gaskets are new. How would that affect fuel bulb bleeding down?

 

[Rivets]

Sounds to me like you have an air leak. When you press on the primer bulb, you are applying pressure on the fuel in the tank, forcing fuel up the pickup tube. Definitely could be that the tank is warpped, allowing air to leak between the carb and tank. You can check this by putting a thin coat of dish soap around the carb base and push hard on the primer. Any bubbles mean a leak. Doubling up on the gasket might help. Where a new tank is not an option, I’ve sealed this area with silicone sealant. Must remember not to spill gas here, as it will damage this seal. Also could be a bad primer bulb, even though it is a new carb.

 

[sgkent]

the cap leaks fuel a little when I turned it over to change the oil. Are you saying the cap is supposed to be a one way valve that holds pressure between when it runs?

 

[Scrubcadet10]

I don't think Mr. Rivets said anything about the fuel cap... ?