The Great Big Lawnmower Thread

The Continental Op

I think I'd take a look at the starter motor itself first? I've had them stuck so you get a relay click but nothing happens at the starter motor. If you can remove it and check it moves OK.

Another issue can be the starter motor cog stuck on the cog ring on the engine. Taking off as much housing as needed and turning the engine with a socket on the flywheel nut sorts that. Thats unlikely as you hear a lot more noise if its stuck at that point.

If there is a solenoid (sometimes built into the starter) then you can risk shorting it out (its just a relay switching a high current to the starter motor) then you can see if it works. More safely you can test it with a meter :-)

deezell

It's starter not getting enough power, bad connection or the battery is knackered. If the voltage drops sufficiently under the starter load so that it extinguishes the panel lamps, then either the battery is bad, you didn't reconnect it fully, or one of the battery cables has a poor joint. Check Live from battery to it first terminal, where smaller live cables are tapped off for the circuit board. This live can go directly to the solenoid if it one. Check the negative line to the mower chassis. A multimeter is your friend, to see where the battery 12v is disappearing.

tombrown

Thanks, I'll try those suggestions.

If it is a bad battery then it should jump start, right?

deezell

Yes, but double check the terminals on the battery, if they're a flat plate terminal it has to be clean metal tight to the lead terminal.

tombrown

Right - I took out the battery, tested it (13v with no load), cleaned up the terminals and then reconnected. Had the battery sitting out of its a compartment while I tried it out, as it is a pain to get in & out.

Anyway, tried it this time & sure enough the engine started to turn over, however the battery terminals immediately went red hot & the plastic on the wires started smoking. So I stopped

Any suggestions for next steps ? :)

deezell

Try recrimping where the wire enters the terminal. There's corrosion inside the crimp on the copper and the inside of the terminal. Ideally you need to cut back the cable to clean wire and crimp on new terminals. If you have solder and a strong iron you could try to get some inside the crimp, but once battery terminal verdigris gets inside the terminal crimp you'll keep getting bad contact until you strip back and crimp new terminals. Plenty of time to get a pair from nearest autoparts.

tombrown

Excellent - thanks. The battery terminals are fairly corroded - i'll clean them up at the same time.

To crimp the terminals, is that something I can do with pliers, or will I need to get them soldered?

deezell

https://www.boards.ie/discussion/comment/120287908#Comment_120287908

You could use a pliers, it might do enough, the problem will be the stripped ends of the cables inside the crimp, they're likely all black and coated, so no amount of crimping will give a clean metal to metal contact. Same with solder, it won't stick to black coated copper. Check the slack on the cables, there may not be enough to cut back too much and crimp. Bad battery terminal crimps are a curse, they'll drop 4 or 5 volts, get hot, leave little for the starter.

tombrown

Plenty of slack in the cables - I'll strip them back. So long as I can crimp the terminals using pliers, and not have to solder them I'll be fine. I am useless with solder :)

tombrown

https://www.boards.ie/discussion/comment/120287648#Comment_120287648

So I stripped back the wires, crimped on new connectors and tried to start. No red hot terminals now, so thats a positive step, engine starting to turnover - another good one. But it only turns over slowly, not enough to start. I've put the battery back on the charger and will try again tomorrow.

At least am heading in the right direction

tombrown

Help needed again, I'm afraid

The battery issue is sorted - the engine turns over nicely now when I try to start it. But it turns & turns & turns and just doesn't catch. It'll keep turning for 2-3 minutes, then the turnover slows and I need to charge the battery again. I've tried two different spark plugs (both brand new).

Remember I took out & cleaned the carburetor - is it possible I have screwed something up when I did that? Any idea what or if there is something else I need to look at?

deezell

https://www.boards.ie/discussion/comment/120302489#Comment_120302489

Did you reconnect throttle and choke cables on the carb. Did you properly install the float valve in the carburettor if you opened this. Is fuel getting through the fuel line up to the carb. Did you open the fuel valve from the tank if fitted. Did you check for a spark at the plug gaps (connect a spare plug and press it to the cylinder to ground. You should have a visible spark when turning over.

tombrown

Thanks - I'll try your suggestions. I am pretty sure I reconnected all the appropriate cables to the carb and fuel lines are OK, but will check it all again.

One thing - not sure what you mean by "connect a spare plug and press it to the cylinder to ground" - can you clarify for the uneducated? :)

deezell

https://www.boards.ie/discussion/comment/120302738#Comment_120302738

To check that there is a spark in the plug when you turnover an engine, you remove the lead from one of the spark plugs in the engine, and plug it onto a spare plug. Place this in contact with the cylinder head or any convenient metal part of the engine. Turn the engine over while looking at the gap end of the plug, the bit that's normally inside in the engine, and you should see a clearly visible spark jump the gap.

tombrown

Plug sparks fine (tested as you suggested)

Fuel line to carb is OK (disconnected from carb, opened in line tap & fuel flowed)

Throttle & choke cables seem OK - see 3 photos (2 - slow throttle, 1 - full throttle, 3 - choke open)

So it looks like I need to take the carb off again & make sure I didn't make any mistakes when I put it back together last time (float etc).

Anything else I should be looking at?

1.jpg

2.jpg

3.jpg

The Continental Op

https://www.boards.ie/discussion/comment/120306505#Comment_120306505

Anything else I should be looking at?

Why you posted three of the same jpegs?

Try seeing if there is any fuel in the float chamber. Just undo the bolt at the bottom of it and it should come off and be full of fuel and then drip (pour) fuel from the needle valve. Then take the float off, side out the pin in the hinge (normally?) the needle should come out fixed to the float, then clean the tip of the float needle and I use a interspace dental brush or similar to very carefully clean the seating.

tombrown

Thanks - I'll try that

They weren't the same JPEG, they were 3 different positions of throttle & choke, which was what I was trying to show

tombrown

just took out the carb.

The (outlet? thinner) air hose was dripping fuel when I disconnected it. Then when I unscrewed the bowl, it was full of fuel. Is that normal or is that a problem?

Sorry for dumb questions, I'm learnign this as I go

deezell

I think you might have caused the float valve to not close, flooding the carb, and engine via the inlet manifold, possibly fuel in the oil. Turn over the engine with the plugs out. Check the oil level to see if its raised, and if it smells of fuel. That small tube is the crankcase vent, shouldn't be fuel in it.

The Continental Op

https://www.boards.ie/discussion/comment/120306710#Comment_120306710

The bowl should be full of fuel and it should carry on running from the float valve unless you lift the float up. If lifting the float doesn't stop the flow thats another issue. One common issue is the valve thats attached to the float getting stuck.

deezell

https://www.boards.ie/discussion/comment/120306769#Comment_120306769

Or if you're not that familiar with carbs, the valve needle can fall out as you dismantle and you might not notice. Oops.

tombrown

Needle is definitely in. Toook it all apart & put it back together again & it still has same effect.

I did turn the engine over with the plug out - nothing came shooting out the plug socket (that I have seen before)

Is it, at this stage, worth me taking the carb off again & taking it to a mower mechanic to try & sort it, or will he need the full mower to fix? As I said before I havent got a hitch at the moment, so cant get the mower to the shop :(

EDIT: After I typed above I realised I had forgotten to reconnect the solenoid wire this last time I put the carb back. Put it back on & the engine started :) Happy days I think.

Woudl that have made a difference? Have I just got lucky this tiem & may have an ongoing problem?

PS - I also checked the oil and it seems OK (at least no smell fo petrol in it)

deezell

Other than running a fine straight wire through the jets, if the mower was left for a long period with petrol in it, its possible that its caused laquering of some of the ports. You can always trickle a drop of petrol, or squirt some brake clean, into the manifold while turning over just to check that the engine is firing and has enough compression. With this test it usually runs for a few seconds, then stops as there's no fuel getting into the air flow. The choke will create considerable suction, and this would normally permit a blocked carb to run badly at least. There may have been moisture in the bowel over the winter, and this reacts with the ethylene in petrol causing corrosion salts or crystals, which will block the main jet. Afaik, there's no solvent to get this out, including petrol itself. Poking with fine wire, and going over every visible port, removing mix and idle screws, its the only way. Maybe give it to your mower guy, he'll know how to clean it, might even have a suitable engine to test it on.

tombrown

Thanks

I'm hoping that when I first stripped the carb maybe I didnt put the needle back in properly, and this time perhapsI sorted that. I did clean it with wire through the various holes & plenty of carb cleaner.

Anyway, its started at least once, so I'll try it this weekend and if it is temperamental I'll take the carb to the mower guy

tombrown

I had it running again this evening and it seems OK. I did notice I need to use the choke each tiem I started it - it used to be first time only, and then it woudl start without the choke after that. But at least I can cut the grass and buy myself a bit of time to sort it out properly.

Should I be swapping out o-rings & gaskets in the carb? (do I dare take it apart again .... :))

deezell

https://www.boards.ie/discussion/comment/120310475#Comment_120310475

Hot starting with the choke sounds like fuel mix too lean, jet still not clear, or the crankcase vent tube loose or split. If you can pick up a gasket set, by all means. The seal from carb to manifold should be good, air in here would affect idling, but unless the carb wasn't tightened down its not a massive running issue. Motorcyclists love/hate their carbs. Thank the stars for fuel injection in cars.

joujoujou

I remember I asked about that last year, I'm however struggling to find it now, so once again - what are your thoughts about ride-on lifting jacks like this:

https://www.donedeal.ie/gardenequipment-for-sale/tracjack-ride-on-mower-lift-jack-free-delivery/27690131

Is it sturdy enough? Is it safe?

On the other note: would the one below be any worse? It's approx 50% cheaper (incl. delivery):

https://www.ebay.ie/itm/333820468833

Thank you.

The Continental Op

...

tombrown

https://www.boards.ie/discussion/comment/120313051#Comment_120313051

Cut the grass with it yesterday, thought i'd really screwed it up when the engine started racing, but then noticed the throttle lever had slipped off the carb. After that was fine. I'll keep an eye on it. At least I got the grass cut :)

Thanks @deezell and @The Continental Op for all the advice to get me through my annual troubles. I'll most likely be back next Feburary :)

joujoujou

Re: my above question - never mind, found it finally. :-P