Wristpin

As Nigel says, but what has been holding the throttle open against the governor's (automatic rev system) desire to close it? Was it a new engine that came with a fixed link to hold the throttle open? I fitted a good few Sprints to Hayterettes over the years and cant recollect encountering any difficulty. An image of your engine with the air filter removed will facilitate a more meaningful answer.

Years since I've seen an Osprey but fairly sure that it will have a mechanically operated choke operated by the throttle cable going past full speed. It was sometimes a bit of a balancing act obtaining both full choke at one extreme of the throttle lever throw and the Stop position at the other. Take the air cleaner off and you should see the choke butterfly. Take an image or two with the air filter removed and post on the forum

This was sent to me by another forum member . Reminds me of the day when most village garages in the UK had a vulcanising machine for tyre repairs.

Just as the original Austin / Morris Minis did. First indication was a stiff / seized choke cable.

A neighbour has just asked me to sort out a Howard Rotavator that has stood unused for twenty years and the fuel tank was in a similar state. Clean now but with more perforations in the bottom than a certain brand of tea bag! Thanks for the birthday wishes from forum members - celebrated with a visit to the dentist for a crown, £££!!! OMG!

You have what was originally called the Hayter 12" Rotary Mower that subsequently acquired the Hawk name. As supplied it would not have had front wheels but just a large diameter anti scalp roller. The wheels were an optional extra. Your comment about it not having any height adjustment is not strictly correct - as you say, there is no lever or other on the move adjuster but if you look at the sides of the chassis there are alternative mounting positions for the wheels and / or the roller. The original machine was then joined by the 19" Hawk Major , the Briggs 13 prefix to the model number signifying a 5HP engine instead of the 3.5HP engine on the 12" machine. Confusingly the Major parts list shows an optional 16" blade. Not sure why anyone would want to put a 16" blade in a 19" chassis. Why was it called a graveyard or cemetery mower? That is what the original machine was designed for ; narrow to get between the headstones, the anti scalp roller to deal with humps and bumps and the nylon rubbing strips to prevent damage to both itself and the masonry. I was told, but cannot confirm, that the original 12" machine was designed at the request of the Commonwealth War Graves Commission for maintaining the orderly and close packed cemeteries both in the UK and in foreign parts. Confusingly Hayter re-used the Hawk name on a light weight version of the 16" Harrier which was mainly sold through the sheds and by mail order leaving the Harrier model name mainly the preserve of the mower trade. https://www.dropbox.com/s/n0qgwb5nfcq725q/Hayter Hawk 12 and Major190001.pdf?dl=0

Think that most points have been covered but what exactly is " caustic acid"?

Very unlikely to be Cycle Thread in that diameter. No reference table for Cycle Thread goes any where near 2" . My guess would be a manufacturer's special.

Basically a generic Chinese built unit but Sealey have a good reputation for after sales back-up. Before committing it may be worth having a word with R-Tech in Gloucester who have a five star reputation for after sales service and often have ex-dem sets at greatly reduced prices.

As has been said, parts should not be a problem, as well as forum members , there are a few breakers who advertise on the bay of evil. Try Stuart Oliver stuart.oliver@btinternet.com Or. 01233 820811

What's the history? Is it new to you and do you know what's been done to it? Has it ever run in your possession? If similar to the image it could be points ignition but more likely electronic - Magnetron. May be a Magnetron sticker in the centre of the debris screen above the flywheel. What's the compression like? Because of the action of the decompressor its difficult to check the compression by pulling the rope. Fold the handles, stand it on its tail, remove and ground the plug lead and then with a gloved hand bounce the blade against compression in the opposite way to normal rotation, ie clockwise when looking at the blade. Doing that fools the decompressor and gives a more accurate view of the state of play. You should get a pronounced bounce. If it's just soggy it's possibly time for a valve job. If you know anyone with a leak down tester it will give you a better view of the state of the piston and rings, the bore, head gasket and valves. Images show a recently overhauled engine undergoing a leak down test and holding pressure - no piston blow by, gasket or valve leaks .

What's the history? Is it new to you and do you know what's been done to it? Has it ever run in your possession? If similar to the image it could be points ignition but more likely electronic - Magnetron. May be a Magnetron sticker in the centre of the debris screen above the flywheel. What's the compression like? Because of the action of the decompressor its difficult to check the compression by pulling the rope. Fold the handles, stand it on its tail, remove and ground the plug lead and then with a gloved hand bounce the blade against compression in the opposite way to normal rotation, ie clockwise when looking at the blade. Doing that fools the decompressor and gives a more accurate view of the state of play. You should get a pronounced bounce. If it's just soggy it's possibly time for a valve job. If you know anyone with a leak down tester it will give you a better view of the state of the piston and rings, the bore, head gasket and valves. Images show a recently overhauled engine undergoing a leak down test and holding pressure - no piston blow by, gasket or valve leaks .

This may be of use https://www.dropbox.com/s/9pa2ow4nz4dixdn/Hayter Osprey and 21 0001.pdf?dl=0

The disc is riveted to a steel flange which is part of the shaft - not listed separately so presumably a welded assembly.

Tip the machine back on the handle bars and put a weight on them. Disconnect and ground the plug lead and then with a glove on bounce the disc against compression in the opposite direction to the way it runs (ie clockwise) . This fools the decompressor profile on the cam into allowing full compression. You should get s pronounced bounce not just a soggy stop . No bounce? remove the head and inspect the bore and if you have access to bore measuring gauges, measure and compare with the figures in the appropriate Briggs manual. Obviously this is best done on a dismantled engine but in-situ will give you a rough idea. If you have a set of new rings you can poke them down the bore and compare end gaps against spec. Might just be valves. Check gaps, remove, inspect and if necessary reface, recut the seats, lap and set gaps.

Quite easy to produce a new disc as it was just a flat alloy sheet riveted to the hub but may be difficult to find somewhere using suitable alloy who will chop you off a bit rather than want to sell you a whole stock size sheet (8' x 4' ?) From memory each blade mounting point was reinforced with riveted on steel plate so has that been torn out as well? If so that would complicate the issue of moving each blade round a bit . Also am I right in thinking that it was not a completely circular disc but had flats between each blade? That would preclude moving the blades round 45 degrees. All adds to the attraction of finding a good used disc but, of course, they never come along when needed!

Same issue with the six cylinder petrol lump in an ex army O type Bedford in the 1960s - that's progress!

Why not ask Emak themselves? Emak UK Ltd , 01543 687660

A cautionary tale and I hope that Adam makes a full recovery. The risk is not just confined to stagnant water. This makes interesting reading for anyone working with animals or on the land. http://www.nhs.uk/Conditions/Leptospirosis/Pages/Introduction.aspx

Don't recall the Hayterette as having an alloy disc, normally steel. However they can fight. With the retaining bolt removed there is a thread in the disc to take a puller bolt or more correctly a " pusher" bolt to force the disc off but if the disc has fought in the past that thread is probably stripped . It's then a question of drilling two holes in the disc just clear of the boss and fabricating a puller . if the crankshaft oil seal has been leaking you may be in luck and be able to draw the disc off without too much of a fight but if not it will need a lot of heat on the boss while protecting the sump with a pile of soaking wet rags. To get sufficient heat into the boss you really need oxy- acetylene . Should say, remove the fuel tank before you start!

Not sure of the validity of this but we were warned not to pre fill with water hotter than the machine's max temp as apparently filling with just boiled water can damage the bonding between the "vibrating thingys" and the bottom of the tank. Perhaps worth bearing in mind.

Those pick up pipes do pull out but so long as the fine mesh on the end of each one is not blocked it's not usually necessary to do so. The only jet fits from the outside at right angles to the venturi , on older carbs the body of the jet screws in and on later ones it's a push fit held in place by a rubber washer and shaped metal washer washer. When refitting the carb to the tank it is necessary to pre tension the diaphragm by leaving all the carb retaining screws slightly loose and having hooked the diaphragm rod into the crank on the choke shaft, hold the choke butterfly open while tightening the screws. When the choke is released it should move smoothly to fully closed. This is better explained with illustrations in the appropriate BS manual.

The blades should be free to swing but we would often find them incorrectly fitted withe the washer above the disc under the nut when it should be between the blade and the disc. Genuine Hayter blades are cranked and can only be fitted one way up. We would find them turned over "to use the other cutting edge" but this restricted their free movement. The cranked design was a carry over from the earlier Hayter Mowers where the rotation of the cutting disc could be reversed to use both edges. The red plastic blocks could be correct ; for instance on one model there was one that slid up and down the height adjustment lever. However we really need images. Can you not sort out your image posting issue? - it will make it far easier to offer meaningful assistance.

Unless you come across a Horwool label somewhere on the chassis, your best bet for dating may be with the Kohler - always assuming that it's the original that is. A Kohler expert may be able to tell you how to unpick the serial number but I have a feeling that a lot of them had the "uncoded" date of manufacture on the id plate. The copy brochure that I posted pre-dates 1978 which was when I acquired it at the liquidation sale of Godfreys of Brenchley near Tonbridge, Kent.