OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines briggs 3.75 hp sprint seizing prob please help

hey guys i got a briggs 3.75 hp sprint and the engine seems to be
seizing and locking up , when i first got the mower i cleaned the carb, checked the diaphram then did the valve clearence, all seemed to be good i also checked the crank to se if was bent or not,then i took the head off decarboned it and checked the bore all was good she fired up first pull reved up and held em nicely,, after a 2 min. it started slowing down and seizing up until it locked up i managed to free it up after 5 mins of rocking the base plate sqwuirting wd down the plug hole . and she started again but ran like a dog, now i did check the oil after this happend and there was a bit that had been thrown onto the dipstick so it has a little bit, but will low oil do this ??? lack of lube somewhere in the motor crating heat makeing it seize up , if not what else could make this happen ??? i also thought these motors had a low oil cut out switch to kill the motor if no oil,

They have no such item as a low oil cut out they are on premium honda ride on engines and stationary motors.

Low oil will cause this, once it has been seized once generally the bottom end is ruined, sometimes you get lucky and they continue to run well again. If there is no oil on the dipstick when you wipe it off and recheck it add some good quality SAE 30 oil and try again.

The symptoms match lubrication failure, but nothing else that comes to mind. You have probably done serious damage to the aluminium bore, and may have scored the big end bearing as well. The cause was probably low oil - you don't run a splash-lubricated engine with the oil level down any more than 1/4" or so from full. It is just possible that the oil slinger on the timing gear drive was damaged, but since you know there was little or no oil in there, that is highly unlikely to have been the problem.

I agree with Joe - it's worth putting in the oil and seeing if it runs well enough to be worth keeping. Chances are it will never smile again, and will use some oil as well as having a rather tender big end bearing, but it might be useful for something.

ok guys thanks heaps thats exactly what it was low oil i put about half a liter in there until it came up on the dipstick and she runs fine a bit ruffer than before but ok...and a bit stiffer on the pull cord so like grump said i may have seized the big end bearing but hopefully after a few runs it might un sieze and loosen up ....maybe I just cant belive only half a liter of missing oil will do that!!!

From dead empty they only hold 600ml, thats 83% lower than the full mark if it took 500ml to fill up

cheers joe i supose the bugger that threw it out must of draind it

Usually they do not damage the bore. Really the only way that happens is with low oil and excess heat.

Ive had one here that was low on oil and grabbed on the bottom of the crank. Ive had another here that was run low on oil and it grabbed on the top of the crank under the flywheel. Id say thats what happened in this instance.
Neither had bad bore damage.
If you had bore damage you would have smoke, either burning it or from crankase breathing.


My mate ran his low on oil and he got it freed up and it ran Ok.


Has the back of the crank case got vertical ribs cast into it???



Not sure about draining it, if you never check the oil it is not hard for it to get down that low. Probably threw it out because it seized.