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Discussion Starter · #1 ·
Hi

I have just replaced the timing belt and water pump on my Honda 4514 ride on mower.

I'm using all genuine Honda parts.
I started the mower and have major leaks from the water pump.

I tightened the bolts to 10nm as per the Honda service manual.
The manual says the bolts are m6.

The bolts on my mower are m8
I am unable to get a wrench on the rear bolt as it's barely accessible and a real pain to tighten.

The service manual states the general torque for 8mm bolts is 24nm.

Could it be I should tighten the water pump bolts to 24nm? It's a big difference.

Really appreciate any help here as driving me mad.

Regards
Richard
 

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If it were mine I'd just tighten them until it quit leaking or they got to being almost too tight.

As for how tight too tight is... well, after you work on stuff for several years you come to know by feel based on the fastener size, what part the fastener is holding, the material the bolt is threaded into, what the gasket type is and other such things.
 

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'81 Gravely tractor, 50's 60's 70's 80's 90's Gravely tractors Various Honda Power equipment
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Make sure you use the genuine Honda coolant, a 'Non Silicate' type or your water pump seal will leak if you use any other brand coolant.
 

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Discussion Starter · #4 ·
If it were mine I'd just tighten them until it quit leaking or they got to being almost too tight.

As for how tight too tight is... well, after you work on stuff for several years you come to know by feel based on the fastener size, what part the fastener is holding, the material the bolt is threaded into, what the gasket type is and other such things.
Many thanks Dixie

Yes, I think I'm going to have another go today and give them a good tighten. Hopefully none will snap 🙄

Regards
Richard
 

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Discussion Starter · #5 ·
Make sure you use the genuine Honda coolant, a 'Non Silicate' type or your water pump seal will leak if you use any other brand coolant.
Many thanks for the reply

This is really interesting as I'm only using plain water to test as don't want to waste any coolant. I'm using prestone antifreeze (ready mixed).

I did use silicone lubricant on the seal before I installed it as am used to doing with coffee machines which I have fixed hundreds of.

Am going to take it off and clean.

Just so much work as gotta remove the flywheel, ignition coils and timing belt again...
 

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It is the type of anti-freeze that caused the seal to leak, the silicon sealant didn't cause a problem with the gasket, it was the water-pump SHAFT seal. It was the silicates in the coolant itself that caused the rubber seal to leak from the type of rubber Honda used for the water-pump shaft seal. There is the rubber seal and a plastic type piece inside that Honda was having the problems with between the impeller and housing.
 

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Many thanks for the reply

This is really interesting as I'm only using plain water to test as don't want to waste any coolant. I'm using prestone antifreeze (ready mixed).

I did use silicone lubricant on the seal before I installed it as am used to doing with coffee machines which I have fixed hundreds of.

Am going to take it off and clean.

Just so much work as gotta remove the flywheel, ignition coils and timing belt again...
I forgot to mention, don't run straight water too long or you can damage the shaft seal. The lubricants in the coolant help lubricate and protect the shaft seal.
The early water pumps used an aluminum pulley that was non replaceable and the pulley was also used for the timing belt tensioner. When the pulley wore it would let the belt get loose and cam timing could jump out of time.
Honda upgraded the pump with a new design that has a steel pulley that is replaceable and upgraded the pulley-impeller shaft seal. That is the seal that would leak out a small weap hole in the housing behind the pulley. The rubber in the seal and plastic/teflon that rubbed against it was affected by the silicates/salycates or however it was spelled, in the coolant and would cause it to leak at the pump shaft.
That is why it was so important to use the 'Honda Only' coolant.
Many people had problems with them leaking because they either used straight water or the wrong type of coolant that damaged the shaft seal in the pump on both power equipment and motorcycles, and also on their automobile engines.
Honda sold their coolant that was already 50/50 premixed that you just poured in and didn't have to dillute.
Some aftermarket companies are now making coolants that are safe for the Honda water pumps. Amsoil coolant is safe for them.
 

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Discussion Starter · #8 ·
Many thanks for this. Makes sense.

I think the prestones coolant will be ok, it says its silicate free.

Is no point me spending a fortune on the Honda coolant as the mower is ancient and I've already spent loads on the water pump, gasket and timing belt. Also a new battery plus had to buy various tools.

I think the charge regulator needs replacing as goes from around 14 volts into the battery at tick over to over 17 volts at high revs. This is turning into a very time consuming and expensive project.

Kind of wishing I'd just bought one that didn't need all the work now.

Regards
Richard
 

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You night have a regulator/rectifier starting to go bad. A possibility a diode is going bad inside it and it is getting A.C. volts along with the D.C. volts being sent to the battery. The A.C. volts would be very high, more than double what the D.C. volts would be and if you are using a digital volt meter to check it at the battery it will show higher than average D.C. volts. Also check to make sure all of your ground connections are good and clean so the current has a good clean path to ground or the over-load can bleed off to the positive side. The regulator part inside the unit can also begin to fail. It should top off around 14.8 volts D.C. at the battery.
It has a 3 phase A.C. output alternator-stator so you want to check each leg of the 3 outputs to make sure you have around 50 volts A.C. or more from each leg of the 3, but it sounds like your stator is working good.
Good luck with the repairs on it, I wish you the best with it. Your engine is basically a 'Half' of a 'Goldwing' motorcycle engine, they were built very reliable and designed for high engine hours on them.
 

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Discussion Starter · #10 ·
Just an update in case anyone is interested.

I took off the water pump today and the oring is snapped. I guess I must have caught it when sliding the pump to adjust timing belt tension.

Have ordered another and hoping I don't do the same thing when fitting this one. 🙄
 

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Use a little bit of silicone grease on the 'O-ring' water pump seal/gasket to help it stick in place, protect the rubber, and help it seal, and lubricates it to let it slide easier when you have to move it to adjust the timing belt tension without damaging the 'O-ring' seal, just a light coating will do and won't clog anything it it breaks off and won't harm the water pump shaft seal.
The other type of silicate in the coolant is of a different type that crystallizes like salt and that's what damages the water pump shaft seal when it crystallizes.
 

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Many thanks for this. Makes sense.

I think the prestones coolant will be ok, it says its silicate free.

Is no point me spending a fortune on the Honda coolant as the mower is ancient and I've already spent loads on the water pump, gasket and timing belt. Also a new battery plus had to buy various tools.

I think the charge regulator needs replacing as goes from around 14 volts into the battery at tick over to over 17 volts at high revs. This is turning into a very time consuming and expensive project.

Kind of wishing I'd just bought one that didn't need all the work now.

Regards
Richard
I can relate to that,,, should have traded it in on a zero turn last fall, my 4514 over this winter: new timing belt, water pump (wasn't leaking, but timing belt had eaten 3/4 of the teeth), radiator, used driveshaft and both dampers, used PTO with replaced bearings, new PTO cable, changed front axle assembly with repaired one, new tires, new deck spindle bearings, drilled idler pulley and replaced bearing, deck belt, that's all so far,,,
Started with "hmmm, should only take 3 hours to replace this PTO bearing,,,


Tire Wheel Automotive tire Motor vehicle Vehicle


Note the teeth are about half as tall and half as wide as they should be.

Automotive tire Motor vehicle Automotive design Steering wheel Steering part
 

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The Aluminum pulley would wear down, that's why Honda changed the pulley to a replaceable Steel pulley so you don't have to replace the water pump.
The older Aluminum pulley was Non Replaceable and when it wore, you had to replace the water pump assembly to get the new pulley, and the aluminum pulleys wore out quicker, especially if the timing belt was set too tight. That's why they improved it with the Steel pulley that was replaceable.
 

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Discussion Starter · #14 ·
That's interesting as I just replaced the water pump on my 4514 and the teeth dont look much higher. It's a new pump.

Got the mower back together today (apart from fitting the deck) and all seems OK.

I will replace the hydro transmission fluid once I can find some that doesn't cost an insane amount.

I replaced the coolant and flushed the system. Also fitted a new thermostat and spent ages refurbing the radiator cap as couldn't find a replacement.
I'm told I should replace the plastic oil pump drive gear. No doubt this is another horrendous job.

Just wondering if anyone has done this.

I think I have to remove the radiator, fan and pto clutch, all of which will be extremely difficult as usual. 🙄

Richard
 

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Yes replace the plastic gear, they wear the teeth off and won't pump oil. That will stall the engine from no oil pressure and the safety interlock will kill the ignition.
You have to remove the radiator and PTO clutch to get at it but can be done with the engine in the frame.
There's a cover to remove and you will see the gear so you can replace it without removing the oil pan.
It's easier on a tractor than a generator were you have to remove the generator unit and rotor, that requires a special rotor removal tool to do it right. Then you have to remove the generator adapter housing to get to the drive gear cover. Replace the cover gasket while you have it apart to help prevent oil leaks.
 

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There is no oil pressure safety interlock on the tractor version of this engine. Which is why I installed an oil pressure gauge on mine. I did replace that gear BTW when I rebuilt the PTO clutch. It was as perfect as the new one I pulled out. I think timely oil changes with good oil play a role here. The previous owner of mine did both. Even though he ran it pretty hard (cutting about twice the grass I had to with mine and he ran it WOT against the governor all the time. I typically did not keeping my RPM about 2500 when I had mine.
As for HST fluid. I can highly recommend Kubota Super UDT2 fluid. I used it in mine and it worked great. It's not cheap but I think it matches or exceeds OEM Honda fluid
 

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Discussion Starter · #17 ·
Yes replace the plastic gear, they wear the teeth off and won't pump oil. That will stall the engine from no oil pressure and the safety interlock will kill the ignition.
You have to remove the radiator and PTO clutch to get at it but can be done with the engine in the frame.
There's a cover to remove and you will see the gear so you can replace it without removing the oil pan.
It's easier on a tractor than a generator were you have to remove the generator unit and rotor, that requires a special rotor removal tool to do it right. Then you have to remove the generator adapter housing to get to the drive gear cover. Replace the cover gasket while you have it apart to help prevent oil leaks.
Many thanks

I am hoping to replace the plastic water pump gear but cannot find the part for sale anywhere.

I'm in the UK which doesn't help

Regards
Richard
 

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It's the oil pump gear, I had to get the number from my Honda rep, I'll try to find it and post it. The gear is available, most part diagrams don't show it separate.
 

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Honda GX360 engine

15140-ZA0-980 Drive Gear oil pump
15138-ZA0-020 Oil Pump Gasket
91301-ZA0-000 O ring Pump cover 45x2.5mm
15142-PH3-003 O Ring 10.8x2.4mm

Those are the Honda part numbers for the gear, gasket and O rings that should be replaced to do the job.
 

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Discussion Starter · #20 ·
Honda GX360 engine

15140-ZA0-980 Drive Gear oil pump
15138-ZA0-020 Oil Pump Gasket
91301-ZA0-000 O ring Pump cover 45x2.5mm
15142-PH3-003 O Ring 10.8x2.4mm

Those are the Honda part numbers for the gear, gasket and O rings that should be replaced to do the job.
Hi and many thanks for the info.

I can get the oring and gasket but no one has the gear available (as mentioned I'm in the UK and it's difficult to find parts for such an old mower) I got the water pump and timing belt from a company in the USA.

Regards
Richard
 
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