Mad Mike
Well-known member
I’d plug the vac line and put a small engine 12v electric pump on the mower. Same price as a vacuum pump ($18), less trouble.
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What did you do in your garage today..?
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@Mad Mike - any special recommendations for 12V pumps?
I studied current pump and don't see any markings for it besides "Mikuni". I know they're all pretty much the same.
Tank is under seat. I installed a new filter from the JD dealer right before doing this work. Had another new OEM filter on it and had the filter in backwards, so replaced it. I know it's not supposed to matter for these filters, except to make it harder to spot debris. Gas is clean in the filter.
Also I should say, the pump is pulling gas just past the filter. However, the way the pump and filter is situated, this means the filter is oriented vertically with the pump maybe 6 or 8 inches above it. So I actually confounded a few things here; because while things are stopping just past the filter (you can see fluid level burbling up and down just slightly beyond the filter), this is also really the first point at which the fuel is drawn vertically. So MAYBE there isn't enough vacuum to actually pull the fuel vertically, or maybe the filter is blocked, or maybe both.
So I guess I have a few things to check when I get back to it next week:
- see if fuel tank is venting properly. Try with fuel cap open.
- see if fuel pump works with gravity feed to pump. Maybe pump needs to be primed?
- try cleaning out fuel pump with carb cleaner.
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Mad Mike
Well-known member
Those older mikuni pumps were used in applications where tanks gas levels were below carbs, gravity could not fill carb bowls. Some bikes and sleds use pumps to keep bowls filled when riding at odd angles.
Rubber diaphragms don’t like ethanol, causes them to stretch or crack. The result is loss of fuel pressure. A rebuild kit costs about $15.
Any $20 vacuum pump off Amazon will work. They may me different looking, but they are interchangeable for small engines.
The upside to electric is they prime and fill bowls once energized. Most low pressure $20 pumps are around 4gph, what’s enough for an RR garden tractor.
Wiring is easy, run a wire from +12v on side of the ignition key to red on the pump, run black on the pump to ground.
Crazies might chime in about adding a tip over circuit. I wouldn’t worry about that unless there’s a chance you’ll loose it and rollover while drifting.
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Malks
Well-known member
I did that a couple of weeks ago. I put a block of wood under the scrape blade to keep rust stains on the floor to a minimum. Yesterday we had a few showers mixed with graupel (ice pellets) up here.
Still have time to clean it up. Kill the rust, a fresh coat of paint and protect it. Might as well keep the bucket from rusting out if its still working good.
I have a tractor with similar setup. Check the short vacuum line that goes into the pump. Mine was deteriorated and cracked and sucking air. I wrapped it with electrical tape and that solved the problem. Later, the pump began spitting fuel out the tiny vent hole occasionally. (Diaphragm damaged) I got a new Mikuni pump, cheap from the dealer, and a new vacuum line (it's about 2" long). When I installed the pump I continued to use the taped up vacuum line. I'll put the new one on later, when the taped one fails.
I think no on the rust proofing. That's exactly what a 35 year old blower should look like.
I replaced the impulse line with new fuel line. Impulse was noticeable with finger at end of fuel lines (original and replaced) and vacuum fluctuations were about the same magnitude ~5 mm inHg/~2.5 PSI.
New pump is $75 at the dealer, which is less than the value of my time spent on this, BUT I actually enjoy this tinkering because I learn something new every time.
I would love to rebuild the pump as part of my play time; I bought a rebuild kit for the pump on my 87 CBR600 and fixed it, but the problem is I can't figure out what model this Mikuni is. The workshop manual doesn't specify either.
https://www.amazon.ca/Anauto-Mikuni...1730044944&sprefix=vaccum+fuel,aps,136&sr=8-3
Change the pump and the fuel lines and you should be good to go. If it has a electric fuel shut off on the carb check that as well. Usually a single wire to the bottom.
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I'll see if I can find a receipt. As I recall, the pump was around 30 bucks maybe.
Thank you @85K100 !
Thanks @Scuba Steve !
Interesting. The item you linked to has a gold bumpy thing pointed to by the arrow. What is that?
The OEM pump has the same thing which I assumed was some sort of branding. It didn’t look like it did anything, but now I am curious?
Pulled up a few other random fuel pumps and they all had the same thing. That can’t be a coincidence?
That is the air filter for the venting of the diaphagm
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I never would have guessed. It looked impervious when I probed it.
It's sintered brass and if it gets plugged up the pump won't work right either
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@Scuba Steve - Bought the pump you recommended. Got back to the cottage and played around a bit.
First I connected some fuel line to the inlet of my OLD pump and stuck the other end in a cup of water. Alternated between drawing in and pushing out air to the impulse line. I could not draw liquid through the pump that way - it'd move a little way from my cup through the hose and then stay there.
Did the same thing with the new pump. Voila, water spurting out of the outlet, so it's clear something was wrong with the pump. We'll see tomorrow (hopefully) if I have a problem at the carb as well. Fingers crossed.
Relax
Well-known member
I've wanted a mill for the longest time, so with the help of @mimico_polak's trailer, I bought one today from @nobbie48. It took us almost 5 hours of shooting the **** and scratching our heads on the best way to move the 500+ lbs without getting hurt. We decided to disassemble some of the major components, and because we both said the obligatory "That's not going anywhere" after strapping them all down, of course I made it home without anything falling off or otherwise getting damaged (no thanks to the surprisingly bumpy route I had to take).
Unloading and positioning the base on the stand using my chain hoist hung from my 4-post lift. If I had a second person to operate the lift, I could have used it to do the lifting, but Bendpak warns against doing that, and this way I could lower and guide it at the same time into the exact position my OCD wanted. I'll try to take more pics as I continue cleaning and assembling.
Unloading and positioning the base on the stand using my chain hoist hung from my 4-post lift. If I had a second person to operate the lift, I could have used it to do the lifting, but Bendpak warns against doing that, and this way I could lower and guide it at the same time into the exact position my OCD wanted. I'll try to take more pics as I continue cleaning and assembling.
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