What was the machine? Not just the engine........we price up for a full service, a chassis service or an engine service, so the customer has a choice. Particularly where cylinder mowers are concerned for example, whereby the customer may just want the cylinder and bottom blade ground (which the average joe doesn't have the equipment or skills to do) but the engine may well be fine, so thats a chassis service only.
If you're suggesting that cost you quoted was just to service the engine alone without touching the rest of the machine, and assuming it is an annual preventative maintenance service and not an engine with a load of pre existing issues, then that's steep. Aside from changing the service items, We drop the float bowls and drain any fuel, clean the float bowl out and blow through the jets, but unless there is already an issue with the carb, we wouldn't automatically remove it or fit a carb kit as that is pointless if it's running fine. New plug, engine oil and air filter. Plus fuel filter and oil filter (if fitted) are the service parts we would automatically fit. Governor/choke/throttle mechanisms and lubricated and adjusted as well, which a lot don't do. Then you have rope/recoil inspection and clean out etc etc. A lot more than an oil change and a wipe over with an oily rag. And a lot more than your garage does nowadays on modern cars, which are just plug and play, with maybe an oil and filter change thrown it, sure for maybe less money, but they proportionately are actually doing less for them money paid...ask them to do what we do on these small engine, but on your car and watch the size of the bill you get! Had a guy said same to me the other week....'my BMW service was only £10 less than what you've charge for my mower' I said, but what did they do as part of the service? He went and got his bill out the car....they charged him an hours labour of £95 PLUS VAT, plus £45 oil, and £25 for a filter....plus a printed off plug in health report...that was it, so it really irks me when people come out with that old chestnut. Our Labour would be to do that Honda engine service on its own would be around 1.5 hours @ £55 per hour. If it were a whole machine- not just the engine, then you would be looking at 2 to 2 1/2 hours, as that would also entail a safety check, blades sharpened and balanced, drive belts and/or chains checked, adjusted and lubricated, wheels tightened and wheel bearings greased. Rear roller bearings greased, clutch cable inspected, adjusted and lubricated, and controls checked and adjusted, gearbox operation and performance checked, then a deep clean of the chassis top and bottom, then anti corrosion spray applied....cleaning alone on even a basic mower that has grass build up can take longer than half an hour if done properly, then dried and polished down after.
Get your garage to do all that on your car for what we would charge for a full service (£130 ish) then you would be looking at substantially more I guarantee