OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Honda Engines HRU173

Hi everyone
i was given a honda hru173 engine, it only has the boss and no disc assy. i guess it takes a disc as the bottom of the boss is flat round with three holes,wondering if anyone can tell me if other model hondas interchange, or if they just have a single bar cutter set up, iv'e never seen underneath one to know. i wouldn't mind getting it set up and see how it goes. thanks micka

I had one, it had a disc with a hole in the middle and 3 prongs to go up into the boss

thanks joe, i sort of know where i'm steering noe, i'll check it out

My one went for scrap, it was getting really clapped out (was pretty sad wjem I got it) The thing that broke it for good was sheer stupidity, a 47 degree day, and plenty of victoria bitter.

Mowing the lawns minding my own business, it was very hot outside and the mower ran out of fuel.... Having not had any fuel laying around the house I put a good half litre of paint thinners in there and soldiered on. The last 20X20 square at my old house was the thickest grass I have ever mowed with any mower, even powertorques struggled with it.

Anyhow I went full steam ahead into that and about 3/4 of the way through I blew the side out of the headgasket and it only kept barely running with a decent bang on every compression stroke.

Afterward I did revive it making a headgasket out of a cereal box but it never ran the same again. Hey I got it for free, it was the second mower I ever got running and I got money for it from the scrap merchant.

haha, that sounds like something i thought only i'd do, cheers mate

I don't know the octane level of paint thinner Joe, but I doubt it would be higher than 60, and it would more likely be less. There will have been some really serious detonation going on in there. If it didn't break the head of the piston, that engine was over-designed.

Was back when I was a lot younger, drunker and stupider lol...

I dont know the octane rating either, it was performing like a rocket while it was running on it until there was a blowout. I may try it again on another old scrap machine. Seems A shame to send something for scrap that has no good use anymore but fun can still be had from

i once ran a toyota forklift on drag racing fuel. it was where i worked almost 10 years ago.
we kept the fuel in old turps drums and the boss had some he filled with methanol for a 1100 horsepower torana [i think maybe it was avgas not sure] i dont know how it ended up with the drums of unleaded, but the forklift sounded a lot different and went much better
the boss heard the way it was running and asked me what id done to it, when i told him id just put some fuel in it and showed him the drum he realised where he had put his racing fuel was very bloody funny to see the look on his face when he told me that was 100 dollars worth of fuel. this was before petrol went over 1 dollar a litre

I admire that approach, Joe, because experiments properly performed are a chance to learn something that will be useful eventually.

Old racing fuel needs to be approached with care, emmo. First, some of it is methanol, and of course a petrol engine won't even run on it - it requires an air fuel ratio of 8 to 1 instead of 14 to 1. Second, a lot of it contains benzene/benzol (two names for the same stuff) which has a high octane but is carcinogenic. You used to be able to buy racing fuels of various octanes up to I think 115, with various levels of benzol, up to almost pure. Nasty stuff to leave laying around.

If an old engine runs better on higher octane fuel, either the ignition timing is over-advanced or it has so much carbon accumulation in the combustion chambers that its compression ratio has increased. Best solution is to begin by checking the ignition timing, then trying to burn out the carbon. Often the carbon build-up has been caused by worn rings causing blow-by and oil consumption - if that is the problem you probably won't be able to burn it out. However I had the problem quite a few years ago and it was caused by feather-footing when driving the car, believe it or not. I'd put a 215 cubic inch Buick in an MGB (the same little aluminium V8 that became the Rover 3500 V8 when Buick dropped it and sold the design and tooling to Rover). Probably unwisely, I'd chosen the Buick Powerpack version, with 4 barrel carburetor and 11 to 1 compression, then ported it considerably and fitted free-low exhaust headers. That engine in its original form had a really bad reputation for carbon accumulation, and since I was driving it to work every day in the Melbourne traffic, I just couldn't keep it from happening.