I have just got hold of a Victa 4 stroke lawnmower with a 4 stroke Ultima engine (from looks I have a guess that it is made by Tecumseh). The mower currently does not run and has been used for several years. I have never worked on one of these engines and just wanted to know where to start in order to get it running again. Also wanted to know if these engines when running are any good if anyone here knows? It seems look quite powerful.
If it is an old Tecumseh engine, the carburetor will have a float bowl and the fuel tank will be above the carburetor. If it is a Briggs & Stratton there will be no float bowl: the fuel tank will be attached to the underside of the carburetor. Or alternatively, just look at the engine itself: does it have a red anodized aluminium plate on it headed "Tecumseh" or "Kirby", or does it have various stickers on it saying "Briggs & Stratton"? My comments on whether the engine is any good would depend on which of these two brands it is, and how old it is. Also, how much power it has depends on which model it is. Tecumseh rotary mower engines are commonly either 2.5 or 3 hp. Briggs & Strattons used on Victas are commonly 3, 3.5 or 4 hp but may be more depending on model. Both Tecumseh and Briggs engines have long series of numbers on them which tell us exactly what model they are. On the Tecumseh it will be on the identification plate. On a Briggs it will be stamped on the blower cowl, near the cylinder head. When we are clear on what engine it is, we can talk about how to make it go.
Pretty sure the ultima is a 5-6hp tecumseh, carby is quite complicated, but generally a good clean and replacing the O rings inside it will have it run again.
Joe, is this one of the late Tecumsehs from shortly before they went under? I've never seen one - I thought Victa stopped using Tecumseh engines in the 1970s, when the B&S engines became available.
It's a 5/6hp 207cc Tecumseh engine alright, does have a float bowl and the there is an air snorkel going up the handle guy I got it off brought it ne in the mid ninties, it's one of the first generation Victa Mulch or Catch mowers. Not sure why it is no going - is it worth having a look at the carby?
If it has good spark it would be worth cleaning the fuuel system, I will leave this one to somone more knowledgable with the more complex carby to give you advice though.
VC Victa, as Joe has said, I suggest you do some preliminary checks before tackling the carburetor - in particular, verify that there is spark and compression, no bad news in the lubricating oil, and the engine turns over nicely without nasty indications of trouble. Then remove the air cleaner, open the throttle and squirt some clean petrol into the intake port. Stand clear of the carburetor in case it spits, ensure the ignition is on and the speed control set in the starting position, and pull it over. If it does not start with two or three pulls and run for a couple of seconds, chances are you have at least one problem that is not the carburetor. If it starts, bellows briefly, then cuts out, you have a useful engine with a fuel supply problem. Clean out the tank, petrol tap, and supply line then verify that you end up with a good fuel supply to the carburetor. See if it then primes using the primer bulb, or close the choke (depending on which it has). See if it starts and runs. If it doesn't run, take a look at the attached carburetor diagram, see if it is the same one you have, and give us an update.
Thanks Grumpy I will do the above checks and let you all know what happens, I will update during the weekend. Also thanks for the carby diagram Grumpy.
Got mower all fixed up (carby seals needed replacing) pulled the cord once and the mower is now spinning without compression, I am pretty sure that the conrod has broken as the blade spins freely in both directions. It did not seem to do this before? Nothing is broken on that outside (ie crankcase is not damaged). I am still not sure what happened mower had plenty of oil, although it was empty when I got it. I am now looking at taking the engine apart and fixing it (this is going to be a project). The first problem is that I cannot get the blade boss off the mower. Is there any easy way of doing this? Secondly do you know what else I should look for inside the motor? I am going to re-hone the cylinder and put in an over size piston (I already have the piston and tools required). I am also obviously going to replace the conrod and any other damaged parts.
If you picked it up with no oil, I would dare say they had run it for a while low on oil. Chances are is the rod has snapped, but its also possible that maybe a valve has jammed (unlikely)
To get a victa blade boss off I generally find I need a fair bit of heat applied and rest the boss against something, put a bolt of the same thread into the crank, and tap the bolt with the weight of the engine hanging off the boss.
I'd begin by seeing whether the piston goes up and down when you rotate the crankshaft. You can do this by removing the spark plug and either looking in through the hole, or bending a piece of tie-wire to reach over toward the bore. At the top of the stroke the piston comes level with the top of the cylinder. If the piston crown does not come up to the top of the bore, you can be sufficiently sure the connecting rod is broken. If the piston goes up and down, you will need to take the cylinder head off to see whether the valves open and close. If the rod broke while the engine was not running, it is fairly likely that it was terminally damaged earlier and just chose this moment to separate completely. That is a piece of luck, because the rod will probably not have damaged the internal parts. You may have no collateral damage other than perhaps a scored crank-pin (due to running without oil, if that is what caused the broken rod). As a rule of thumb, rods are broken either due to lack of oil, or by over-revving the engine. Over-revving usually doesn't damage the crankpin, but running dry probably will have.
Took the bottom off the engine and the connecting rod has broken into several pieces and has damaged the camshaft. However no other damage has been done, piston, governor and all housings are all fine in fact with these parts removed engine seems to be in great condition. From the look of how dry all the parts where (even after I added all the oil) I would say that the damage was caused by lack of oil. I am going to get replacement parts (if available) and rebuild the engine. Does any one have any diagrams of how this engine should be assembled?
Be sure the piston and bore are not scored. They usually are at least superficially scratched if it has run dry long enough to break the rod. Look for longitudinal marks on piston and bore. Check the ring gap: remove rings from piston, place them one at a time in the bore about 10 mm down from the top, and check the ring gap with feeler gauges.
Bore is fine no marks at all. Piston rings are also in great condition and fit into the bore correctly, however there is a small chunk from the bottom od the pistion missing. Does this mean that I need to get a new piston?
I have also checked over complete engine and now know what damage has been done.
The engine requires a new connecting rod, camshaft, governor and a gasket set. I went down to the local mower shop and they said parts for these engines are not available in New Zealand and said it would cost around $1000 to get the parts required.
I have sent a email to outdoorking hoping that the guys here have the parts that I require for a bit less than $1000.
This is a question of whether you are doing a full repair or just getting it running again. The fit of the piston skirt is one of the critical aspects of making the engine durable and quiet. If your piston is missing a chunk of skirt, it is quite likely to be cracked and mishapen. You are spending money on this project - it probably won't cost much more to make it a reliable job.
We've all done less-than perfect repairs on old machines to save money, but they have to be capable of working. I once "fixed" a set of worn-out car pistons by widening the top ring grooves on a lathe and putting steel rail rings beside the new compression rings as spacers. The original ring grooves had worn out of square, and this was a way to fix that - the car was unusual enough for a new set of original pistons to be expensive. Even so, I wouldn't have done it if I'd been trying to make it into a good-as-new car; I figured it would be commensurate with the condition of the rest of the car. It was successful as far as it went: I drove it 30,000 miles and sold it in good condition.
After looking into cost of parts I decided that the cost was just too high to fix up engine. I have instead brought a rebuilt Briggs & Stratton Quantum 35 engine (engine was cheaper than parts would have cost) and fitted that to the mower along with new blades. The mower now runs like new, these briggs engines are great. Very powerful but they run smooth as. I may end up keeping this one for myself.
