Manual Blade Clutch Issues: Mountfield 725 / Castelgarden EL63 - Lawn Mower Forums : Lawnmower Reviews, Repair, Pricing and Discussion Forum
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post #1 of 4 (permalink) Old 06-15-2017, 06:55 PM Thread Starter
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Manual Blade Clutch Issues: Mountfield 725 / Castelgarden EL63

Hello mower experts!

Iím hoping that some of you might have experienced the same issue that I have just now and can point me in the right direction. Apologies if Iím not using the correct terminology below, but Iím sure that youíll help me out with this.

Background Info:
Iím completely new to ride on mowers, but not scared of a bit of oil and grease. I recently bought two fairly sick and neglected Mountfield 725M ride on mowers. Neither in working order, but the previous owner assured me the between the two of them, there was one good working mower. I bought both of them and started to dismantle the good bits off one and reconstruct on the other.

So far Iíve replaced the pulley start mechanism on the B&S 65 Intek engine, bought a new blade mount bracket and more recently a new blade clutch. The clutch being the expensive and most problematic area. All the wiring and safety switches have been disabled, but thatís a job for later, once Iíve got the clutch sorted. So yes, this is a manual pull start mower for the time being.

Before I started to tinker with the ďgood mowerĒ, the one that would start, I noticed that whilst the mower would drive ok, the engine would stall when I attempted to engage the blade to cut grass. For those of you not familiar with this mower, it has many variants, like the Castelgarden EL63, all fitted with a manual blade clutch engage lever. The lever actuation allows the main engine drive shaft to engage with the clutch plate which itself is attached to the blade.

My Problem Statement:
I have fitted a completely new clutch mechanism (lower and upper section), checked the tension and engage springs lengths (all good) and adjusted the engage lever tension to satisfactory settings. When starting the mower, the blade clutch should be disengaged, for safety reasons, but I cannot start the engine when the blade clutch is engaged. It feels like it is locked. However, if I set the blade clutch lever to the forward (engage blade) position, the engine starts, it feels heavy when doing so, but it does start, and obviously the blades are now spinning. So, my mower is now cutting grass, but itís not safe. Iíve got two young children, so whilst Iím happy that I can now use it as a mower, I want to be able to switch everything off using all options, should anything go awry. First thing is to make sure that the blade spins only when I want it to.

The fitting of the new clutch involves securing the upper fixed mechanism to the underside of the cutting deck, with the main drive shaft connecting to the smooth (upper) clutch drive plate, and the lower half, with the coarse clutch plate which the blade mount bracket is fixed to, held in place by a bolt that is secured to the main engine drive shaft. There is a bearing mechanism in the middle of the lower clutch part that should, in theory, allow the engine to spin the securing bolt independent from the coarse clutch plate. The way I see it is that the blade clutch plate should only spin when the clutch lever is engaged and the clutch plate is forced to mate with the inner section of the upper (smooth) clutch drive plate. Does this sound correct?

Iíve attempted to adjust the tension on the main blot that keeps the lower clutch plate in place, but I cannot see any way of securing it without it locking up against the fixed part of the clutch mechanism. By securing the bolt, the coarse clutch plate is forced up against the fixed element of the upper clutch mechanism, and can only spin (with the engine) when the clutch is engaged, forcing the coarse plate to mate with the smooth drive plate. I think thatís the theory anyway.

Has anyone had any similar issues with these types of blade clutch? Iíve seen loads of similar clutch parts on the web, so Iím hoping that this is fairly common to some of you and that you can see the error of my ways fairly quickly.

I should add that I have the workshop manual for this, and there is nothing in there to suggest that there is anything particularly clever about the mechanism. Iím now beginning to wonder if Iím being daft and missing something obvious.

Any help or suggestions would be appreciated.

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post #2 of 4 (permalink) Old 06-17-2017, 01:46 AM
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Hi G,
For some reason the forum software hid your post in moderation so the other members could not see it. I manually released it so the others can see it now which might help you get some replies.

I'm not familiar with those clutches at all. You did very well explaining what is going on but maybe if you could get us a picture or two of it would help? Maybe it would look like something one of us here in the US has run across before.

Mark - 2002 John Deere LT150H

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post #3 of 4 (permalink) Old 06-17-2017, 09:32 AM
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If I read correctly, the mounting of the lower portion causes the clutch to "mate" and essentially be engaged? If that's correct, my question would be, what does the lever to "engage" the blade do then? What is it hooked to? Is it a mechanical control that's supposed to be moving something to cause the clutch engagement, or is it a lever that functionally is just a switch for electrical? My initial guess was just that somewhere in the wiring, with the engagement lever NOT engaged, the electrical system sees a fault (most likely a "not in neutral" message). By putting the lever in the engage position, you've tricked the electrical to believing neutral no longer matters, it now believes it's already running (even though it's not even started yet). Don't know if that makes sense or not. Your question is much more clearly written than my suggestion for what to check
Oh, and by the way
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post #4 of 4 (permalink) Old 06-19-2017, 06:00 PM Thread Starter
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Hi jtclays, firstly, many thanks for taking the time to read my post and replying. Much appreciated.

In answer to the queries, it is a manual lever clutch, which operates via a lever that pulls on a metal threaded cable (like a break cable) that is hooked onto the engage paddle on the upper section of the clutch. This type clutch of clutch is typically found on a push mower. I've included a link to a picture that might help.

When mounting the lower section, the lower clutch plate grips onto a metal of the upper (fixed) section. The blade engage lever, when actuated (engaged) allows the inner drive wheel to mate to the lower clutch plate and therefore spin the blade. The lever actuation should displace the upper face plate, freeing the lower clutch plate and allowing it spin in sync with the main drive shaft. Again, I think that this is how it should work.

I've taken the lower clutch section off again recently and confirmed that the central bearing should allow the main drive shaft to spin through the centre of the clutch plate, independently.
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