Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.You're currently viewing our forum as a guest. This means you are limited to certain areas of the board and there are features you can't use and images you can't see. Registration is simple, fast, and completely free. If you're already a member please log in to your account to access all of our features: Join our community! |
| Need small fuel pump for lawn mower engine swap; Kohler Courage finally gave it up! | |
|---|---|
| Tweet Topic Started: Sep 29 2014, 01:36 PM (4,682 Views) | |
| cwatkin | Sep 29 2014, 01:36 PM Post #1 |
![]()
|
My Kohler Courage based mower continued to burn more oil and run hotter with time. I changed the oil and it seemed to just get worse each time I mowed. It was also starting to lose power and seemed like it was running hot. A fresh change of Rotella synthetic was broken down into tar after like one mowing. Knowing it was about toast, I began topping it off with used oil from one of my cars. I think it must have eaten a ring or something as it got really bad and then locked up on me. I have located a replacement engine for cheap but some adaptation will be required. My biggest concern is how the gas tank sits at the level of the engine. There is a small vacuum operated pump off the engine to boost the pressure to the carb. The carb on the used replacement engine sits higher and there is no pump/vacuum port on the engine. I was thinking about a small 12v pump connected to the ignition so it always runs as long as the key is in the on position. If so, what pressure should I look for? I am guessing not much. Anyway, I am open to suggestions to do this swap. Conor |
![]() |
|
| aartod | Sep 29 2014, 03:24 PM Post #2 |
![]()
|
If you have a existing vacuum port on the new engine, briggs has a vacuum operated fuel pump part # 808656 that should work just fine. If you use a electric fuel pump more than likely the pressure will be too much for the needle valve int the carb and flood the float bowl! |
![]() |
|
| Good bye | Sep 29 2014, 06:01 PM Post #3 |
![]()
|
I would drill a hole in the manifold and use the original fuel pump. |
![]() |
|
| JamesGarfield | Dec 12 2014, 07:35 PM Post #4 |
|
Member
![]() ![]() ![]() ![]() ![]()
|
Hey Connor, I just found your post about putting an electric fuel pump on your mower. I'm wondering if you were still planning on doing this mod, or if you have already done it, or if you dropped the idea and moved on, or what. I've done this upgrade on a mid 90's Wards Signature mower (MTD-600) with the Briggs twin. Turns out it was a little more involved than first expected, but the end results have been quite good. I could post details on the project here if there's any interest. James Edited by JamesGarfield, Dec 12 2014, 07:37 PM.
|
![]() |
|
| rmcelwee | Dec 13 2014, 08:41 AM Post #5 |
![]()
|
This thread makes me want to put a G10 in my John Deere... |
![]() |
|
| cwatkin | Dec 13 2014, 01:37 PM Post #6 |
![]()
|
I actually haven't done anything with this as of yet. Weather changed and so did my mowing needs. I have one working mower and two that don't. I am a little unsure if I would be better off looking for another engine rather than using this one. I know I could sell it for more than I paid so I have left it intact on the donor mower. I might sell it as it stands or pull the engine. The stupid previous owner ruined a perfectly good mower rigging it so he didn't have to buy a $5 part. I don't know what he was thinking but the mower is junk now. Anyway, if you have suggestions, I would appreciate it. The bolt-up and electronic mods are not an issue for me. The fuel issue is my main worry as of now. Conor |
![]() |
|
| JamesGarfield | Dec 14 2014, 02:04 AM Post #7 |
|
Member
![]() ![]() ![]() ![]() ![]()
|
Hi Connor, A while back, I read somewhere about the advantages of upgrading to an electric fuel pump. Then my old Wards Signature started getting hard to start, then it wouldn't idle smoothly, and was displaying signs of weak fuel flow. I figured the fuel pump diaphragm had probably been weakened by ethanol in the gas. So if I'm gonna go in and do fuel pump work, why not use this as the chance to try out the electric pump. There's that old saying, "If it ain't broke, don't fix it." The little vacuum diaphragm fuel pump used on many engines is a marvelous device. It's rated to lift gasoline from 4' down, and deliver it to the carburetor at 1.5 PSI. But like in your case, if you're installing an engine that doesn't have the internal diaphragm fuel pump, converting to an electric fuel pump can get ya mowing again. The electric fuel pump provides performance improvements such as faster cold-starts, and a smoother, more powerful engine output since fuel is provided evenly at all power settings. You sound like you know your way around wrenches and wires, which is great because it simplifies everything below :). PARTS NEEDED Autobest F4027 Electric Fuel Pump http://www.amazon.com/gp/product/B00496RE82/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1 Spectre Performance 2517 Inline Fuel Pressure Regulator http://www.amazon.com/gp/product/B000CQ46H0/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1 Voltage Regulator (something like this one) http://www.amazon.com/gp/product/B00K3JZVCU/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1 Approximately 12" of 1/4 fuel hose, and a half-dozen hose clamps. Approximately 2 feet of hookup wire, with associated crimps, heat shrinks, etc. Total cost will be somewhere between $50 and $75, depending on if you need a voltage regulator, and how much of the hardware such as hose clamps and screws you have laying around. THE SCHEMATIC The installation of the electric pump and associated components is fairly logical and straightforward: [IMG][URL=http://s1361.photobucket.com/user/HermanLeopold/media/FuelPumpDiagram_zps039d9f2d.jpg.html] [/URL][/IMG]As has been mentioned, the Electric Pump will provide an output pressure of 4 to 5 PSI. This can be too much pressure for the need valve in the carburetor, so the Inline Fuel Pressure regulator is used to drop the pressure to about 3PSI. The Spectre 2517 Regulator has a large dial selector on the top, which makes it easy to adjust. It's always a good ide to use a fuel filter in your mowers, so one is included here. The Fuel Cutoff Valve is another good thing to have, although it becomes somewhat redundant now because the electric pump blocks fuel flow when it's powered off. PARTS LAYOUT Exactly where you install the components will depend on the physical layout of your particular mower. As an example, here's the layout of how the parts went in on my old Wards Signature: [IMG][URL=http://s1361.photobucket.com/user/HermanLeopold/media/FuelPump5_zps055f50cd.jpg.html] [/URL][/IMG]Try to route the hoses away from hot exhaust components. As you can see on the right, my carb had the diaphragm fuel pump. The two blocked off hoses are from the no-longer-needed vacuum pulse line coming from the crankcase. CLEAN VOLTAGE IS NEEDED FOR THE FUEL PUMP Most lower-end mowers don't have a voltage regulator. They just take the AC from the alternator coil, and use a couple of diodes to rectify it into 'dirty DC' which is used to charge the battery while the engine is running. This is inexpensive and generally effective, though it's hard on the battery (no regulation of the charge current). The Autobest fuel pump is quite rugged, however it does NOT like running on this 'dirty DC'. It will work for a while, but the voltage spikes in the 'dirty DC' will make this pump burn up and fail within about 30 minutes. If your mower does not have a true voltage regulator, you'll need to install one between the switched Vbatt source, and the '+' connector on the electric fuel pump. Any generic automotive electronic regulator rated for 12V, negative gnd, 3A or more, should work. (You can use a scope if you want, and see the difference between the 'dirty DC' coming off the alternator, and the regulated DC output from the regulator.) I didn't go into lots of detail on where to mount the regulator (it can fit up under the backside of the dash). You'll know your way around installing it. When it's all hooked up properly, you'll be able to hear the electric pump softly vibrating when you turn the mower ignition switch to 'ON'. MODIFY THE DIAPHRAM IF NECESSARY If your carburetor does not use the internal diaphragm fuel pump, then you can hook the output of the pressure regulator to the fuel inlet, set the dial to about 3psi, and you're ready to go. If your carb DOES have the internal diaphragm fuel pump, it will be necessary to punch some holes in it. (This will be about the only 'non-reversible' part of this upgrade, although new diaphragms are available if you wish to reverse the mod.) The diaphragm uses vacuum pressure pulses from the engine crankcase, to make it flutter rapidly and pump fuel into the carb. If the diaphragm isn't moving, it will block fuel trying to flow in from the electric pump. The diaphragm could simply be removed, but some carburetor designs use the diaphragm as a gasket, so it might need to still be present. The fix is to open up the fuel pump face on the carburetor, and pierce about a half dozen 1mm holes in the center. This will let fuel flow through the diaphragm even though it isn't moving. Put it all back together, hook up the hose from the regulator set to 3psi, and that's it. SET THE REGULATOR PRESSURE 3psi is a good ballpark figure for the initial regulator setting. Most healthy needle valves can handle this pressure. If there should be signs of carb flooding, the pressure can be dialed back some. If the engine is experiencing 'lean surge' at idle, then dial UP the pressure some. Briggs engines don't like ethanol in the fuel. As of about 4 years ago, they can tolerate E10, but the book says no-no on anything higher. The fuel pump diaphragm is one of the parts most vulnerable to ethanol damage. One additional advantage to the electric fuel pump upgrade is you won't be needing the diaphragm any more, so you don't have to worry about further ethanol damage there. ROCK AND ROLL! Once I got this system tweaked in, the mower performed better than it has in all of it's 20 years. Turn the ignition key to ON and hear the pump running. Startup happens within 1 second of cranking, even when cold. Depending on how you use your mower, the engine will purr like a Kitten around a well-maintained yard... or it can roar like a Lion if you want to go bushhogging with it. Hope this was helpful (?). If you decide to do it, post back and let us know how it goes. Good luck! |
![]() |
|
| cwatkin | Dec 17 2014, 10:45 AM Post #8 |
![]()
|
Thanks. I appreciate the parts list and how-to for this modification. I was thinking I wouldn't need a voltage regulator at first but then read about concerns over "dirty" DC voltage which may be an issue on this unit. I know there are rectifier diodes on this unit but don't know how good they are at making clean power. So the battery won't do much smoothing of this spiky DC power? Someone on another forum just suggested that I tap into the crankcase breather system to run the old fuel pump. I would think this would work but how would I do this without messing up the breather system itself? Conor |
![]() |
|
| JamesGarfield | Dec 18 2014, 04:36 AM Post #9 |
|
Member
![]() ![]() ![]() ![]() ![]()
|
Hi again Connor, Some of the higher-end mowers do come with fully-regulated automotive-style electrical systems. On these, the electric fuel pump should work without needing an additional regulator. And like you, I also thought that the battery (being like a big capacitor) would smooth out the spiky DC power... but, nope... it'll still kill the pump. The casing of that Autobest pump is crimped closed at the factory, making it impossible to open for repair. But, the unit is fairly inexpensive at about 18 bucks, should it... ahem... need to be replaced. Let's just say I got more practice than I ever wanted at replacing the pump, in the process of learning the hard way about the dirty DC issue. IF you can get your engine to deliver the vacuum/pressure pulses to run your old fuel pump, honestly that would be the simpler and easier way to go. In my case, something apparently went wrong inside the crankcase of this engine, to the point it wasn't delivering any more pressure pulses. I checked out and replaced all the breather system stuff, no go. I really didn't want to tear open the engine just for this, so I figured, let's try out that electric pump idea. And after working thru the various bugs, here we are :). One beauty of the electric pump system is, other than punching those holes in the old diaphragm, everything is easily reversible should you find it desirable at some future point to go back to the pressure pulse system. Looks like you're getting good advice from the forums. Looking forward to seeing how it all works out for you! James |
![]() |
|
| JamesGarfield | Jun 5 2015, 10:40 AM Post #10 |
|
Member
![]() ![]() ![]() ![]() ![]()
|
For those who may be following this thread, here's an update as of June 2015. The conversion is working well. The mower has wonderful power. However, I can no longer recommend the Autobest fuel pump listed in the original parts list. At a bit over 1 year into the project, I've had 3 of these Autobest pumps fail, which is of course unacceptable. One of them worked for 6 months, and another failed after 1 hour. I suppose there's a reason the Autobest pump was the cheapest one on Amazon. At this point I'm testing a couple of other electric fuel pumps from Carter and Airtex. They're more expensive, but hopefully they'll last longer. These pumps MAY even be able to work without the voltage regulator. I'll report results here as they become available. |
![]() |
|
| cwatkin | Jun 10 2015, 05:39 PM Post #11 |
![]()
|
This whole project kinda got put on hold for the time being but I think I will get back to it relatively soon. I ended up buying another rider when this one was really acting up and was later given one that had been sitting and left to rot in the elements for 3 years. I figured that one was going to be parts and scrap but I had it running within 30 minutes of getting it home. It looked rough but runs. As for the other one, I am going to have to find or more likely make a few parts for this engine. The dumbass who had it before me is one of those who messes up more than he fixes. As for the fuel feed, I think I am going to use a gravity feed system with a tank at a level over the engine. This new engine is so wide that I am not going to be able to use the hood anyway. It is a horizontally opposed Kohler Magnum so it is really wide but not that much from front to back. The exhaust comes out the front so I will put the tank towards the back of the engine but at a higher level. This is how the one I was given works so plan to copy that setup and use a tank specified for that mower mounted on some brackets. That way if something were to leak, it wouldn't go right onto the hot exhaust. I hate to abandon the 3 or so gallon tank under the seat as that is nice and convenient but see the gravity feed adaption as the most simplistic, especially since I can't use the hood anyway. Conor |
![]() |
|
| ONEHARDHEAD | Jun 17 2015, 07:52 PM Post #12 |
![]()
|
The vacuum diaphragm pumps are very efficient and dependable. We use them on racing karts using far more fuel than you ever will. I don't think I would go to the expense of an electric pump, and safety issues with the electric pump would bother me as well. |
![]() |
|
| 1 user reading this topic (1 Guest and 0 Anonymous) | |
| « Previous Topic · The Geo Metro Lounge · Next Topic » |


Welcome to the all new Geo Metro Forum. We hope you enjoy your visit.







![]](http://z3.ifrm.com/static/1/pip_r.png)
[/URL][/IMG]
[/URL][/IMG]
7:40 PM Jul 10