OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs & Stratton 375 Sprint

Can I use Unleaded fuel or do I need LRP for this motor? The date code is 930113.

Use unleaded I am pretty sure originally there was even a sticker on them to say unleaded fuel only or similar

It's my understanding that all new petrol engines manufactured or sold in Australia after 1986 were required to run on unleaded fuel. I know it definately applied to motor vehicles.

Hi Joe, talking of unleaded...my best mates vehicle is a 2004 Mazda 3, SP23 which needs to run on ULP or Premium ULP.
The problem is, apparently the oil companies (at least in NSW) can add up to 10% ethanol to ULP (without a warning label on the petrol pump) and his on-board computer engine management system (EMS) detects the ethanol and up comes the engine fault light on the dash.

He then has to take it to a repairer who hooks it up to his outboard computer to clear the error message, which states ethanol present....who then charges him $55 for the privilege.
He has to clear the error message because he needs to be warned if something else goes awry....
He is not a happy chappy.

Heres a little general info.

Any engine that is of alloy head construction will run ULP fuel with no ill effects. Why?? Because the head is alloy it will be fitted with hardened seats.

Why was lead in fuel?? to lubricate the valve seat in cast iron heads as they were just cut into the face of the head.


So any alloy block Briggs and Stratton side valve engine will run perfectly well on ULP because the block has hardened seats in it.

Thanks for the replies. I have been using 2 stroke Victas since my dad bought the first Mustang in 1974 & these run on any petrol. My 1986 Bronco needed new rings & rebore at a cost of ZAR1100 (a new Chinese 160cc 4 stroke mower costs ZAR2099). So I gave the Victa to the shop & bought a used Rolux Hornet with Sprint motor for ZAR300.

Thats close to half the price of a new one. It probably would have been worth it give that the Bronco you had was built with about 15-20 years service in mind and a new chinese anything is anything from 2 mins to 2 years.

Not sure what your exchange rate is but you could have bought a piston and rings off eBay for under AU$60 posted to you.

I cut the back lawn (+/_ 250 sq metres) & picked up a few problems:
1. Not much difference in revs between slow & fast, even though the throttle moves all the way.
2. The kill switch does not always work. I had put a lug on the wire & connected to the carby. The kill wire was just that: a bare wire to short to ground.
3. It seems to have fuel starvation, as every 60 metres or so, it begins to miss & dies. A couple of pumps on the primer and it starts again. I soon learnt to pump the primer as soon as the missing began and could then carry on mowing. Any suggestions?

Docker, it seems you have two different problems: the governor speed lever is not moving full stroke, and there is a fuel supply issue. The speed lever movement problem is likely to be due to a Bowden cable malfunction, probably the cable inner is kinked at one end (this happens a lot with miscellaneous Chinese mowers). The fuel supply issue could be any of several things. You will need to check fuel flow from the tank to the carburetor, and if it isn't that, the carburetor will need to be cleaned and checked. With suction-type carburetors I begin by checking whether there is rubbish inside the fuel tank. If there is, the tank and carburetor need to be removed, the tank separated from the carburetor, and the suction pipe filter on the underside of the carburetor inspected. It is likely to be partly blocked with garbage. If so it needs to be cleaned, usually by removing the suction pipe.

Success!
I pulled the carby & blew (or sucked) it out. Re-installed and found that the governor spring was hooking on the throttle lever. I bent the plate upwards at the cable end so that the governor spring clears the throttle lever which now opens all the way. No more cutting out or limited revs.
I also picked up a Wolf mower with Briggs 2 stroke motor for ZAR400. The chassis is not so hot, but the motor runs perfectly.

That sounds like success Docker, you have taken actions that should have fixed both of the underlying problems. Incidentally, it sounds as if the speed control lever or the governor plate had become bent downward due to a mishap along the way. By straightening it you have put things back the way Briggs intended them to be.

The Briggs 2 stroke engine, which was designed and manufactured by Komatsu, seems to have been quite a good engine. There are two or three other Japanese 2 stroke mower engines which are approximately equally good, but were not sold by Briggs and Stratton.

Since your problems are cured, I'll close this thread. If any member wishes to post to it, just send a Private Message to a moderator.