OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Four Stroke Lawn Mower Frames Rover Regal Problem

Hi all, cool site!

I have a problem with a Rover Regal mower. It starts OK runs for period of time, then dies. May last for 15 minutes, but the operating time when started hot is definitely less. Seems to get quite hot, but don't normally handle the engine directly, so just guessing about high temperature.

The possible cause.... My son overfilled the engine oil by about 200ml (800 vs 600ml) last oil change, wondering if too high an oil pressure could have broken something inside? The engine spins freely, no strange mettalic noises when running, and starts first time when cold.

The odd thing, took the cover off the carburettor, throttle controls the butterfly with a spring arrangement, not too sure how this works, but it works fine. But when the engine dies, the throttle butterfly is forced WIDE open and will not move freely at all, and stays that way for a period of time, thens frees up of it's own accord. Mower will then restart (but with more difficulty than when cold, and run again, then dies agains, and the procedure starts again.

So, possible causes IMO FUEL maybe the cap was on too tight, causing a partial vacuum and fuel starvation, AIR filter not allowing enough air into the mixture, filters are old, and I am about to replace them or SPARK, just put in new spark plug, with no improvement. There is not much else is there?

Interesting, just ran the mower with NO air filters and the fuel cap very loose, and it ran and ran and ran. But with no load on motor, no cutting grass. So I am going to go now and replace filters and spring (seems a bit slack) and see if this fixes the problem.

Just wondering if you have experienced this type of intermittent stalling before, and have any ideas what may be the problem?

Thank you in advance for all your help.

David

does it have spark straight after it stops?

Yes, it does....

I have a problem with a Rover Regal mower. It starts OK runs for period of time, then dies. May last for 15 minutes, but the operating time when started hot is definitely less. Seems to get quite hot, but don't normally handle the engine directly, so just guessing about high temperature.



Every mower I have runs hot enough to turn water into steam after use.



The possible cause.... My son overfilled the engine oil by about 200ml (800 vs 600ml) last oil change, wondering if too high an oil pressure could have broken something inside? The engine spins freely, no strange mettalic noises when running, and starts first time when cold.



Most if not all 4stroke mowers dont have oil pressure as such, most have a attachment on the cam that flings it about the crankcase.



The odd thing, took the cover off the carburettor, throttle controls the butterfly with a spring arrangement, not too sure how this works, but it works fine. But when the engine dies, the throttle butterfly is forced WIDE open and will not move freely at all, and stays that way for a period of time, thens frees up of it's own accord. Mower will then restart (but with more difficulty than when cold, and run again, then dies agains, and the procedure starts again.



The throttle arrangement works by....

The fan on the top of the motor pushes against the plastic flap attached to the throttle on the carby, at running speed it will keep the revs steady, if you hit a hard patch of grass and the motor begins to slow down (therefore less air blowing against the plastic flap) it will open up the throttle some more for some extra guts. When the motor stops, there is nothing pushing on the plastic flap so the spring you meantion will pull the throttle open.



So, possible causes IMO FUEL maybe the cap was on too tight, causing a partial vacuum and fuel starvation, AIR filter not allowing enough air into the mixture, filters are old, and I am about to replace them or SPARK, just put in new spark plug, with no improvement. There is not much else is there?



Air filter may make a small difference, the fuel cap being on tight shouldn't as most have fuel caps that are semi ventilated anyway.



Interesting, just ran the mower with NO air filters and the fuel cap very loose, and it ran and ran and ran. But with no load on motor, no cutting grass. So I am going to go now and replace filters and spring (seems a bit slack) and see if this fixes the problem.



If it is just sitting there running it will not get as hot as say if it is actually working doing something like cutting grass, the spring being slack is fine, dont shorten it as it will make the motor rev like crazy.



When you pull the cord very slowly on the compression stroke, if you listen carefully can you hear air hissing out the exhaust? This can indicate a leaking valve.

It is a possibility that the steel valve seat on the exhaust side of things has come adrift from the alloy block, I have had reasonable success when this has happened of repairing by taking off the head and using a center punch to spread some of the allow right next to the valve seat to hold it in. I nearly always use the same head gasket without dramas unless it comes apart.

Another thing that may have happened is your valve seats are worn, after the motor warms up the gap between the valve and the seat will expand enough to cause a loss of compression bad enough that it will not run until it cools down.

I had one a long time back that the diaphragm in the carby was shot, each time it got warm it wouldn't run. Most times however it will run either really poorly from word go or not at all with a stuffed diaphragm.

Do you have some picks of your machine? if nothing else put up what motor you are looking for in the items wanted section and I am sure someone on here can help you out.