Mountfield 725M ride on

[Changy]

Okay, so it isn't on my bench, but I am working on one 

A local garden maintenance business asked me to look at the mower; their client wanted it running.

The machine requires some TLC, but it seems workable. I tried the usual suspects, spark plug. Air filter, Carburettor by using easy start, checking the spark. I noticed the breather pipe missing, but I couldn't see that being the issue. I started cleaning the cr@p to allow a better view of things, and the client came out to see how I was getting on. I noticed a significant gap on one side of the magneto, so I adjusted it. I pointed out some of the shoddy work from a recent "service" and asked the client if he had driven over a rock. His reply gave me a clue because he said his son hit a huge rock which bent the blade beyond repair! 

I dropped an absolute clanger because I didn't have my impact wrench. The drive is clutch controlled so that I couldn't wedge something against the blade 

I assume that if his son hit a massive rock as he did, the engaged drive would shift the flywheel key.

It has a B&S Intek Pro 65 OHV engine, but I couldn't find an engine number despite a search on the crankcase and engine. @Mick, please tell me if there is a significant variance in flywheel keys. I'm hoping I can obtain some keys without too much bother.

If someone has a link for the keys, please could they share it?

TIA

Changy

[Mick]

Flywheel key is 222698 which is the standard aluminium key used on nearly all Briggs engines.

https://www.gardenhirespares.co.uk/2566-briggs-stratton-flywheel-key.html

[Changy]

Thanks, Mick.

I'm investing in the correct flywheel puller. Is it the Flywheel Puller - 19203

Would the key shear despite the clutch? I suppose more importantly could it have damaged the clutch?

[Mick]

You can see if the key has gone before you remove the flywheel, just remove the starter cup off the top and look down at the keyway, you can usually see if it's sheared. Nice thing about the briggs stuff is you can see both keyways on the crank and flywheel from the top.

A little advice though regarding those mowers. I run a mile if anyone asks me to repair one, they are problematic at best. 

[Changy]

You can see if the key has gone before you remove the flywheel, just remove the starter cup off the top and look down at the keyway, you can usually see if it's sheared. Nice thing about the briggs stuff is you can see both keyways on the crank and flywheel from the top.

A little advice though regarding those mowers. I run a mile if anyone asks me to repair one, they are problematic at best. 

The biggest problem is the lack of access to the components. I agreed to look at it because my mate asked me. The local mower businesses wanted £80 to simply look at it.

I want to get a flywheel puller, but I'm unsure which model suits the B&S Intek 65 engine.

[Mick]

I want to get a flywheel puller, but I'm unsure which model suits the B&S Intek 65 engine.

Don't hold me to it, but I think the puller you need is this one, 19069

Although I have various pullers some OEM ones and several I made over the years, it's a long time since I actually bought one. lol..

Actually while I was typing I came across this page https://www.briggsbits.co.uk/acatalog/Briggs-and-Stratton-Intek-Edge-55-60-65-Engine-Spare-Parts.html

If you scroll near the bottom you'll see the puller I mentioned.

[Changy]

Yes, it is 19069, but things worsened.

Please add your view on my attempts to start this engine. It had a new air filter and spark plug, and the previous business cleaned the carburettor. I checked the flywheel key, and it was correctly aligned.

1. Sprayed easy start in the air intake. The engine didn't start
2. Checked for spark using tester; good spark.
3. Checked the carburettor and found water in the float bowl. 
4. Drained the fuel and cleaned the carburettor. I added new clean fuel; it still wouldn't start.
5. Spoke with the owner, and he decided to not spend more money.

The machine isn't in great condition, and I asked him if he wanted me to keep trying? I said he really should consider putting the money toward another machine.

I hate to walk away from a machine without fixing it, but what else could I do?

Thanks

Changy

[Mick]

Did you check inside the valve cover, it might have a bent pushrod or broken rocker so only one valve opening. 

[Changy]

Did you check inside the valve cover, it might have a bent pushrod or broken rocker, so only one valve opening. 

Sorry, I forgot to mention that. Yes, I checked that today when looking at the flywheel key. I did expect the flywheel to be the issue, but despite hitting a boulder it was fine.

I know that all sensors should be clear before an electronic start is allowed, but you can pull-start the engine which bypasses them. Or in my case, you can't pull-start it!

It does annoy me!

[Mick]

all sensors should be clear before an electronic start is allowed, but you can pull-start the engine which bypasses them. Or in my case, you can't pull-start it!

Safety circuit should still be active even when pull starting, parking brake on, blade off etc. Otherwise you won't get a spark.
 

[Changy]

Safety circuit should still be active even when pull starting, parking brake on, blade off etc. Otherwise, you won't get a spark.
 

This is what confuses me. I get a spark when using the pull start, and the only sensor I know is open is for the grass box. The client says it always started manually with the box off, but not electronically.

Does the safety system ground the coil to prevent the spark?

[Mick]

Does the safety system ground the coil to prevent the spark?

Yes, that's how it works. The safety circuit is connected to the stop wire on the engine. It should also prevent starting on the key if certain requirements are not met.
 

[Changy]

Thanks, Mick; I chatted with the guy today and will recheck the machine. I found so many issues with it that I confused myself and didn't do enough with it in the end.

I will temporarily remove the coil ground wire and recheck the spark before rechecking fuel delivery.

[Changy]

@Mick, how hot does a breather pipe get? This mower is missing the breather pipe. I have some flexible hose but I don't know if it is heat resistant.

[Mick]

how hot does a breather pipe get? This mower is missing the breather pipe. I have some flexible hose but I don't know if it is heat resistant.

Doesn't really get hot as such, they are normally made of pretty low grade rubber and moulded to shape to stop them kinking should they need a bend in them.