Author Topic: Pump maintenance FYI  (Read 2569 times)


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Pump maintenance FYI
« on: March 08, 2013, 08:53:53 PM »
Good day all,
I had this information on another forum and figured I'd put it here also for you folks to read and hopefully it helps out. Those Chinese pumps work ok but here are a few tips for extending the engine life. Our shop fabs prospecting equipment and we're also a Briggs & Stratton dealer/warranty center, Kohler, Tanaka, Troy Bilt, etc. The absolute biggest thing you can do for those engines is oil changes and a clean air filter. Obviously this is good for any engine, but you need to be religious on the cheaper engines. Also most of the time the air filter is a simple piece of foam pressed between 2 pieces of plastic and doesn't make the best seal. I have retrofitted a few engines with aftermarket air filters that filter much better and the round adapters that go on the carb and seal better than the plastic stock assembly. Luckily these engines are used extensively in the go kart world so aftermarket parts are plentiful. Here is the link to the aftermarket air filters and adapters, also the 6.5 hp is what they call a Honda GX200 "clone".

I've had good success going to a round clamp on filter and adapter for the Chinese engines. Also with the oil use regular old conventional 20w50, 30 weight etc, on the first 10 hours or so. This will ensure a proper break in and check the oil often while breaking in the engine as it will use some. After about 10 hours you can switch to a synthetic oil if you like, but not during break in as the synthetics won't allow the rings to wear in and seat properly.

 I forgot to mention a few more key items when dealing with the Chinese engines. First thing when you unpack that bad boy grab your metric wrench set and give it a good once over making sure all fasteners are tight. I've seen more than one brand new Harbor Freight engine/pump, etc with loose bolts or random bolts that fell out during shipment in the bottom of the box. Again this is good for any new engine you get but I've never unpacked a Briggs or Honda and had loose fasteners. The next important thing is once you get through the break in period remove the extremely poor quality Chinese spark plug and throw it as far you can. These spark plug are complete crap (I think they called a "Torch" spark plug). Since during the break in process you'll be burning oil might as well burn it on that poor quality plug, after break in put in a good one. I personally like NGK, but you'll do fine with an NGK, Denso or a Champion. Go out and buy yourself 2 new plugs of whatever brand you like. Change the first one after break in and put the other in your tool box. With the new overhead valve engines and better emission standards on the engines they run cooler and cleaner than the old "L" head engines (the older Briggs types with the valves right next to the piston in the block) and you'll rarely foul a plug but if you do it's good to have one and a wrench to change it or your trip could be over real quick. I'll put the spark plug cross reference numbers below to save you the aggravation of trying to find them since my Briggs dealer manuals have them readily accessible.

Here are the plug numbers and these will work with the Honda or clone engines both GX160 and GX200

NGK = BPR6ES or BP6ES (the "R" is just a resistor for radio interference so either plug will work equally well. If you have an older engine that uses oil you can go to a hotter plug such as a BPR5ES or BR5ES to reduce fouling. With the higher temps the engines run on dredges, I always suggest the cooler plug to start with.

Denso = W20EPR-U
Champion = RN9YC (may be a little harder to find than the NGK or Denso)

With that you should be in good shape. Trust me that Chinese "Torch" spark plug will leave you high and dry at the worst possible time so do some preventative maintenance now and throw it out.

 If you ever have a no start situation the first thing to check is the gas then check the oil. These engines have a low oil shut down and I can't tell you haw many engines I've had in the shop with the no start or no spark complaint that was simply low on oil. If the engine oil level is low it kills the spark to the engine to prevent damage and it won't start or run. If you keep the air filter clean and the oil changed religiously it will last a while, they just can't be abused.

Ok now for the crankshaft if your replacing a Briggs or Honda engine with a "clone" engine. The pump side of the crankshaft has a 5/8 threaded shaft. Some of the clone engines I have seen aren't an actual 5/8" they're actually 16mm (5/8" in .625" inches and the 16 mm is .629" inches). That doesn't seem like much, but the impeller WON'T fit without machining. Definitely be cautious when ordering clone engines as this little mix up could cost more in machining fees then ordering another Briggs or Honda engine.
  Now on the shade tree mechanic side I have heard of people turning on their engines and with the crank turning put a bastard file and/or sandpaper to the crank to "turn it down" but I don't endorse or recommend this procedure as it is not accurate a misfitting or mis-aligned impeller will destroy the pump housing.

One last thing after your done running your pump for the day pull the drain plug and flush it out thoroughly. What tends to happen is small bits if sand, dirt, gravel will settle to the bottom of the pump housing. After a while the sand and dirt will dry up and form a concrete like substance. The next time you fire up your pump that "concrete" will start grinding away at your impeller and you'll begin to notice pressure losses due to the impeller getting smaller and/or the housing getting bigger and the increased tolerances will create a loss of pressure. Take an extra minute and flush the pump out good!

If anyone has any questions please feel free to email me at anytime, advice is free and just may save you some money and headaches!

I hope this helps, Chris

Chris Robertson