GMC 4HP 460mm Lawn Mower RL504 Questions & Answers

Hi Diane I would suggest You perhaps try wherever the Mower was purchased from. Hope this helps! Bella

Hi. All I can suggest is to ask Your place of Purchase. Or perhaps Google Your query! Good Luck Cheers

Thanks for your kind advice.

Very interested to find that myself, have you managed to find it anywhere?

No please, not yet. Thanks

Looking for one also GMC catcher

Honda blades fit

Your Briggs & Stratton runs on unleaded fuel and has a wet sump. This is located on the left side (if standing behind the mower, as in normal use of the mower) and is the oil filler/drain, usually with a black plastic butterfly style oil plug/dip stick that you unscrew and use to check the oil level. Use 10w-30w oil if needed, do not overfill and change it every 12 months or earlier in very dry, dusty regions. Happy Mowing!

No longer in production, your only chance is finding one second hand (very long shot!). Otherwise keep picking up catchers from nature strip collections until you find one you can modify to fit with aluminium strips, wire etc. Pain in the A** to do, but it's easier to find an abandoned Nature strip mower with a catcher and swap the motor over. That's what I had to do!

If it has a Briggs & Stratton engine, and you are talking about the Foam Filter located above the carburetor, you can purchase one new from any mower shop, Super Cheap Auto or I have seen them in Bunnings as well. If it is a "honeycomb" rectangular air filter, from a different model engine, again, take it into your local mower shop for a replacement. Not expensive, also get a new spark plug and blades if needed. Change the oil with fresh 10W-30 motor oil and your mower will run like new. (Most B&S motors take 590ml of oil).

Unavailable new for many years. You can try modifying another brand (found on Nature Strip?) to fit. Some soft catchers with wire frames can also be bent to fit if you find the right one. I find it easier to refit the motor onto another brand of mower that has a catcher (these also sometimes found on kerbside rubbish).

Unfortunately no longer available. If your current catcher can't be patched up, then the best you can do is look on Nature strip hard rubbish collections for a possible replacement that could be modified to fit.

If it has a Briggs & Stratton 4-stroke motor, they take 580ml of 10-30 grade engine oil. Change it and the plug every two years and your motor will last forever (well, nearly forever).

When I had to get new blades for my mower, I actually ordered them from England on ebay. I suppose you could try: external link  I don't know what they are like but they seem to have a lot of stuff.

Holy Cow! buying blades from England? Most Mower shops have alternatives that suit. I use Honda blades in mine, perfect fit. Catcher covers, lucky if you can buy one anywhere. If machine is a few years old, usually "NLA" (no longer available) as designs change every couple of years. Try the English supplier but otherwise do what others do, pick up catchers from the naturestrip until you find one you can modify to fit. I have 18-20 used catchers on hand but nothing to fit a GMC. Looking for one myself to suit a spare GMC I have.

do you have a link to the blade you brought, mine needs replacing :)

most of the blades gmc are available to bunnings .... just have a look i found my 4 blades for a RL504 for 40$....

Sure can, just that cheapskate manufacturers only put two blades on to save a buck. First thing I did when I got my mower. You will get better cutting and grass pickup as well, as the blades provide a suction effect as they twirl around. The GMC will use Honda Blades that are available everywhere.

Sounds like a Briggs & Stratton 35 Classic motor, means it will be a 4-stroke motor. They are a good mower, will last for years longer if it's been looked after.

If there are 2 filler caps (fuel and oil separate) then it is 4 stroke. If it has only 1 cap, (fuel and oil mixture) then it is 2 stroke.

You will need to find a GMC dealer locally and see if he can order one for you. If your machine is an old one, then the cost (if available) will be more than the value of your mower. I pick catchers up off nature strips when I see them, but haven't yet found one to suit a GMC. (I have a salvage GMC waiting on me to repair it but it has no catcher.)

Thanks David, mine is probably over 10 years old. Been looking out for one on eBay to salvage a second hand catcher. Might be best just buying a new mower.

Hi Gary, Take the old one out of the mower and go to any mower shop, Bunnings or even Repco or SuperCheap and ask for the same one. I usually go to Bunnings as they are closer to me, if the same brand is not on the shelf, there is usually a book that will convert your brand of plug to the suitable one on the shelf. If your mower has a Briggs & Stratton motor they are usually a Champion RJ19LM plug and about $7 to buy. Put one in every two years, clean the air filter as well and get trouble free starting always. I have picked up mowers on roadside collections and just put in a new plug in to get a great goer!

Nope, just a straightforward push mower.

No according to the definition of "Mulch Mowing" here: external link 

The GMC is not. It Is just a catcher mower.