Carb idea not a problem.

**joe_db** · 02-26-2018, 11:52 AM

Originally posted by CajunSpike View Post

I just got my A4 running smoothly and thought I'd toss this out there.
One of the fixes was replacing a messy clogged carb with a fresh clean one.

While I'm sure this isn't an earth shattering idea, I rigged the electric fuel pump to an separate manual on/off switch in the power line, so even if the key switch/power is on, I can turn off the electric pump.

Why?

After seeing all the filthy clogged up carburetors that sat for a long time between runs, I figured having a switch in the line would let me cut off the fuel flow to the carb so the motor could run till the carb is empty. That would leave nothing to gunk/evaporate/clog the carb bowl.

I've done this on generators, outboards, and just about every kind of engine who's life includes sitting for long periods of time.

Every one starts right up when the switch/valve is reopened.

Obviously this won't help with a mechanical pump, but if there is a method to do it on that system, why not? My original tank has an on/off valve near the fuel line connection. That would serve the same purpose.

Comments welcome.

My boat has been wired this way for a long time. When I am done for the day I shut the pump off and let the engine run the fuel out. Same way any airplane is shut down and same way outboards have been shut down for generations (well we pull the hose off, but same effect).

**joe_db** · 02-26-2018, 01:01 PM

EDIT -
If I am using the engine again that day, I let the fuel pressure fall to zero and shut off right then. If I am done for the day, I let it keep running until the engine stops. Helps I can see my fuel pressure from the helm

**tenders** · 02-26-2018, 11:27 PM

My issue with that setup would be that letting the engine decide when it shuts down would mean I would not be holding the key in my hand turning off the ignition when it happened. Coil damage would likely soon ensue.

Wouldn’t be worth the risk in my opinion. I use StaBil both in and out of season, and haven’t found ethanol to be a problem even after each of the two seasons I didn’t launch the boat (fuel at least 18 months old). I do run the previous season’s tank down to fumes before refilling it in the spring however.

I also use StaBil in my garage jerrycans for the snowthrower, power washer, and portable generator. Never an ethanol problem, though a carb did get gummed up from fully-evaporated fuel after several years of disuse. But that was easily cleaned and wasn’t the ethanol’s fault.

Now, what about an ignition alarm that sounds when the ignition is on but the battery voltage is lower than 13?

**joe_db** · 02-27-2018, 10:24 AM

My alarm is loud and hard to ignore if you leave the ignition on. The oil pressure falls to 0 and sets it off

I have a three terminal OPSS. Two terminals run the fuel pump when oil pressure is up and the third one goes to ground when oil pressure is down. They don't all do this, so take care to buy the correct version.

**CajunSpike** · 02-27-2018, 02:04 PM

My intent would be to sit there waiting till the motor dies, so the ignition could be switched off.

Valid concern noted and welcome.

**joe_db** · 02-27-2018, 03:19 PM

An oil pressure alarm is a good thing anyway