How to replace the diaphragm and gasket on a briggs and stratton petrol lawnmower

[@RestorersShed]

G'day MowerMan - I've probably repaired at least 2 dozen mowers doing exactly as you described in this video :) but my current effort - a Briggs and Stratton 500 Series still Revs up and Down after replacing the diaphragm and Gasket - first time this has happened. I gave the carby a very good clean - flushed with Throttle Body Cleaner and then washed in my UltraSonic Cleaner. Made sure the jets were clean, took off the tube and blew it through with my compressor. I have bought your DVD and I note in that you talk about the seal between the carby and the inlet manifold, in particular the two little washers (black one and white one) - so I have made sure they are in good condition and making a good seal - still Revving Up and Down. I began to take it personally - so I have done the following: 1: Replaced the Spark Plug 2: Clean Fuel 3: Ran it both with and without the Air Filter 4: Replaced the entire carby with a different one (which I know works on another mower) 5: Replaced the Coil ....and its still Revving Up and down - I'm out of ideas!!! Help me MowerMan-kenobi Cheers.

[@MowerMan]

Restorers Shed Hi change the carb and petrol tank. Sometimes just changing the carburettor onto the same tank doesn't help. Remove the recoil cover and look at the opposite end of the inlet manifold make sure the gasket is good. I would also replace the head gasket and particularly check the flywheel key and make sure the blade is correctly on the blade adapter. Sometimes with flathead engines the valves are worn causing running issues. Unfortunately they don't have adjustment like overhead valve models so the only option is to replace or grind the valves and seats to obtain the correct clearance. Like you say you have repaired dozens without issue and sometimes when I get this problem I break a mower down for spares and make more than I would for a sale. My advice would be to move and repair any others and not get bogged down. Make sure the kill switch is clean and its not overfilled with oil also. Hope this helps. Really glad you found the DVD useful and you have started repairing for profit. Hope this helps

[@RestorersShed]

@@MowerMan Cheers Mower Man - I'm away for two weeks for work, but as soon as I get back I'll get stuck in with your suggestions and let you know how I go. Thanks again.

[@zarrow50]

@@RestorersShed or change the Lawn Mower

[@richardkarl6727]

I had the same problem. Cleaned the Carby, adjusted the Ignition coil, etc. I found it was the Springs and the Governor blade.. The Governor blade needed to be filed at the bottom slightly to allow free movement. And the springs were either too tight or too loose.

[@joelbrandon6807]

pro trick: watch movies at flixzone. Me and my gf have been using them for watching a lot of movies these days.

[@marcguy156]

Thank you very much. I followed this fantastic video and fixed my revving up and down problem. You're the best, Mower Man!

[@strathstrathmore9482]

This is a superb bit of detail. My John Deere R40 does exactly as you describe. Your video provides enough detail to give me the confidence to have a go at the repair. I've just ordered a diaphragm and gasket...

[@strathstrathmore9482]

Just replaced the diaphragm and gasket. Gave the tank and carb a good clean with some carb cleaner spray and put it all back together. Fuelled and primed... A couple of pulls in the starter and it is running like it did when it was new. Now revving up and down. No puffs of black smoke. Fantastic video and advice.

[@MowerMan]

Hi glad I could help.

[@danwiddon3854]

As we begin to emerge from the COVID-19 pandemic I found your excellent videos long after you began selling your DVD to monetise your free marketing. Diaphragm and gasket on order for our Sovereign XC35 which needs a thorough clean before I reassemble the carburettor and tank in the hope that a spruce up and new d&g is all our trusty push along needs. Thank you (new subscriber tempting the algorithm to help your cause).

[@chalkuswhiteus9277]

At last, great detailed advice by someone who knows what they are talking about. I changed the diaphragm on my 450 B&S as it was hunting. Now it runs perfectly. Do NOT lose the spring from inside the carb😂

[@MowerMan]

Top Job!

[@EmersonCampbell-t4z]

Thank you for that thorough explanation, I believe I can now work on my engine, once again thanks.

[@shazmeister2005]

Fantastic video mate really helpful. Thought I would just drop you a note with my recent saga. My mower was running poorly, revving up and down and quite a bit of black smoke and dirty plug (my thoughts were it’s running rich). I gave the carb a clean up as I knew that had been an issue in the past as there was visibly debris in the fuel tank, so I drained the fuel tank and cleaned it out too. I also took the chance to remove the head and give it a clean up, lot of carbon build up. I had ordered a replacement diaphragm and gasket and head gasket, but after watching your video and point about the genuine parts I checked and realised the ones I ordered weren’t genuine Briggs ones so I ordered a genuine diaphragm and gasket too. The parts all came and I put everything back together with the genuine diaphragm and gasket.... alas still the same. I replaced the spark plug and got some fresh fuel even though I was pretty sure they weren’t the issue. I was ready to throw the lot in the bin but really needed to cut the grass so thought I would have one last roll of the dice, so I put in the non-genuine diaphragm and gasket, lo and behold it’s now running like a dream! Sorry that epic tale took a while but my question is have you had issues with genuine parts before? I’m pretty sure I had everything surgically clean but maybe when I did the final clean up before putting in the non OEM parts I dislodged a stubborn bit of dirt? I was cleaning everything with copious amounts of carb spray, unfortunately I don’t have a compressor and air line which is the ideal tool for the job. But anyway I got there, thanks for the videos they are great!

[@BionicRusty]

Thank you so much for your brilliant videos. You have helped me identify and repair my trusty Mountfield. People such as you who take the time to load videos with helping other people in mind are what make KZbin brilliant. I can’t thank you enough. Keep up the good work. 🌾🌱

[@MowerMan]

WayneVaughan Jones Glad I could help thanks for watching! Hope you subscribed! It's free !

[@BionicRusty]

Mower Man Thank you. I have. Now a subscribed viewer 😉 Happy fixing.

[@stewartbeveridge1564]

Thanks Mate, this is exactly what my Briggs and Stratton is doing. I found today that one of the bolts holding the assembly on was loose so I suspect that the gasget is the culprit as per your instruction.

[@mellasone]

Great explanatory video, I am now empowered to go ahead and fix my mower's carburetor which has been playing up causing spark plug to go black almost instantly and cease the motor. Thanks a million

[@Doris-y5v]

You explain things so well and wit details ,e.g removing the filters and complete demonstraition .I am beginner and I have been having trouble with surging ,you explained it with the "how it sounds " which helped to know about it that involved the repairs other videos have not explained the same way.Can the gasget be glued ? mine is separated Thank you for the video.

[@meetthehanlons6146]

Done all the steps on my sp470 runs like a dream now thankyou

[@MowerMan]

Meet the Hanlon's That's great! Thanks for commenting

[@petroflorence7962]

Nice job might do mine

[@johnblack4636]

Thanks mate from Australia

[@MowerMan]

No worries.

[@GK-qc5ry]

Great video. My one seems to be misfiring with some slowing down. When I take the spark plug out it's black, so the mix is too rich I think. Will the diaphragm and gasket replacement be the best thing to do?

[@MGB-learning]

Great video

[@johnmcclintock3276]

Hi, I’ve followed your guide to replacing diaphragm and gasket on my Briggs & Stratton engine. Unfortunately the petrol is weeping out at new gasket. Any easy remedies. I did tighten up on refit same way as you would on car wheel nuts, tightening diagonally and not over tightened. 🤔

[@simonm29]

Hello mate, I’ve got a briggs and Stratton 35 my primer bulb isn’t working, I got a new one and it’s still not pulling up fuel? I’d appreciate any advice on further investigations.

[@andrewkneath5260]

Thanks for the video I changed the D and G. But my mower is still hunting I cleaned the mesh on the tubes put in fresh petrol and it still hunts 😂

[@MowerMan]

Andrew Kneath Make sure you use a genuine diaphragm and gasket. I like to keep a spare tank and carb setup that I know works. What I do is swap it over to see if its a carb issue. Make sure the 2 seal washers are seated correctly when you refit and there isn't a split in the primer bulb.

[@andrewkneath5260]

Cheers mate I will give that a go the D an G was a Briggs and Stratton part from the mower shop it hunts and doesn't stop it keeps running but just keeps hunting 😢

[@gradyhernandez4699]

Do a Tecumseh carburetor.mine is leaking

[@MowerMan]

@@gradyhernandez4699 Done one it's on here somewhere

[@federicobacher]

Hi Mower Man, i did all. But something is not working. I test and i have a good spark, i inject gasoline and WD40 direct to the combustion chamber and i can not get an explosion. I cant figure out why.. any advice? thanks !

[@mariowake3785]

Some of the Links need revisiting

[@MowerMan]

in the description?

[@mariowake3785]

Links Not Working

[@kevinthompson6986]

What’s up with English guys calling a gas tank a petrol tank?

[@larrylagoon6405]

to much lead video garbarge