OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Tecumseh / Kirby Engines Tecumseh Ultima 207cc - Another thread!

Hi there everyone, myself, my father and grandfather run a power equipment repair shop in NSW Australia (Honda & Jonsered mostly) and we're a bit stumped on a machine that came into our shop a few weeks back. One of these Victa Ultima 207cc machines with a Tecumseh ULT50 engine.

I've been working with them for about a year now and this is the first Tecumseh engine I've seen come in, so its safe to say I dont have a great deal of knowledge on engines from this manufacturer.

So this is where we're at with the engine:

Upon book in, this description was taken from the customer - "Runs but shuts down after approx. 5 minutes, upon restart machine repeats at less that 5 minute intervals - Repair and service as required"

The oil was overfilled & grotty so it was replaced, along with new air filters in the snorkel, new spark plug (NGK BM6A) and topped up the fuel and ran the machine for about 30 minutes with no trouble but when the throttle is opened to full, or the mower was pushed into grass, it dies.
We pulled the carby off and some of the gaskets were corroded or missing entirely so we ordered up some replacements from our supplier.
Jump to 6 weeks later (Parts had to come from the USA)and we disassemble the carby and clean it, put in a new o-ring, fit up the new gaskets & heat shield/air baffle.

Ran the machine again and it starts okay but once again it still dies if you open up the throttle too quick (even if its at operating temperatue) or push it into the grass.

So, I guess our question is where do we go from here? There doesnt seem to be a great deal of adjustment in the governer arm and we've covered all the other bases.


Sorry about such a long post, but all the facts first time round makes it easier for someone to help I guess. Thanks guys

How is the compression pressure? Burned valves could account for most or all of your symptoms. (I suggest you check the tappet clearances as part of the same investigation.)
Have you checked the free fuel flow rate out of the fuel tank? (It could be starving for fuel under load.)
Have you tried inserting an in-line spark tester when you run it under load? It could be coil break-down.
Is the air filter clean and correctly assembled? (Obstructed filter could make it rich under load - you could probably detect this from the exhaust smell.)
A governor problem does not seem to be a good fit for the problem, since it seems to be temperature sensitive.

At this stage I'd say the leaky valves are the best fit for your symptoms, but the other items should be checked anyway.

They do have a somewhat problematic carburettor and are pretty darn sensitive. I would hazard a guess at two things, either the carb is not 100% (After several of these I still have to have a couple of goes at cleaning them) or the ignition is breaking down.

I do have two of them currently in my parts pile should you need any second hand parts.

I have a rule with ultima motors.

If it runs, change the oil and sell it quick smart.

If it does not run, pull it off throw it in the scrap pile and put a different motor on it. Power torque off a rusty base for the win, makes it twice the mower the ultima ever will be.

Being a dealer, you would be able to get a new 450 briggs and fit that for the owner. Probably less than the cost of fixing the Ultima.

If its on a steel base i would suggest the owner buy a new mower. Well depending on its condition.

I thend to have the same mentality with them Bob, I've had a couple turn up this year, but none of them in any condition to bother with.

The sadest one was when i headed out to a house to pick up a scrap/donation mower, the lady went into the shed, and imerged with an older, but decent Honda, sadly this was only to get to the Ultima, so not only was my excitment at seeing the honda comming out shattered when it turned out not to be the donation, but it was only further trampled by the sight of the steel base ultima, off which i got practically nothing!

You didn't need that "but" in the "older but decent Honda", Ty: if it was a 4-height-adjuster one, in terms of frame durability it is in a class of its own. Heavy, yes, and being pre-75 dBA regulations, noisier than later ones, but a permanent investment. I haven't decided yet whether I'd rather mow with the old or the new (I'm currently researching that) but I have no doubt at all which will last longer. After twenty-odd years of commercial use, my old one is as solid as a rock. On the other hand they worked so hard at making it unable to kill the operator, it is a bit like a lady from Queen Victoria's time: a lot of kit there to ensure nothing went wrong and exposed a flying rock/lady's ankle to the public view.

Is that the one I got?

My last one from Ty, I was excited to see one in great condition, the next day I gave the rope a pull and it went first go, I went inside toget a beer and come back to a huge cloud of smoke and no mower or yard to be seen. I think I have put it back in a corner to pull apart some day.

Personally I'm with grumpy and Bob on this one, The "ultima" or "vector" as they are called in the US are some of the most problematic and shoddily built engines you could ever find on a lawnmower, so I'm sorry to say but its a shame you put any money in it at all, because its really not worth it...

As Bob said if it has a Alloy base repower it, but if it has a steel base..... tell the customer to buy a new mower...


Kori

What a piece of crap these are I no matter what I do can not get the carby to work pulled down put back together many many times but still no joy It starts wen u put fuel down inlet but then dies saying that I think I may sacrifice it to the mower gods thou they seem to be getting a lot lately funnily enough it's mostly Tecumseh No wonder web I get them there always pulled down that's my meaningless post for today
Y

Hiy, Ive just gotten one of these things given to me, never seen or heard of them b4, some of my questions are already answered above, Tecumseh engine, ok, surprising that such an old US small engine specialist has produced a bit of a lemon.
Ultima 207cc , Victa aluminium chassis

At this stage, mine simply has no spark at the lead.
Havent removed covers yet to see what they consist of.
Do they have similiar setup with the magnetic pulley and little magneto coil thing near it as B&S Sprint etc?
since judging from here even if I do get it running may be other issues (it has also spent some time parked out in weather) I will toss up if to have a go getting it going, or get rid of it as a parts wreck, or stick a spare ex-masport 3.75 sprint engine on it I have, if they fit the bolt pattern?

Studying other examples of these things and the carbs that everyone seems to cite, I notice there seem to be two styles of carb anyway, one with a metal float-holder and brass nut like the paper-filter Briggs engines used to have..

and one with a black plastic bottom, 3 PH screws and spring catch, as mine has.
Mine definitely has a u/s coil, all tests on the mower give a negative result for spark, dead as dodo, Im curious to see if the thing runs if I managed to get a serviceable coil, but with what people say re the carbs, and the valves and oil-burning, I guess chances of it running properly even if I got it to fire, are modest.
To aggravate that, this one also had a petrol tank half full of water, dont know how that got there, maybe kid's playing...naturally that water had flowed down into the carb, Ive dried it all out now, but with a carb reputed as 'sensitive"...sensitive is a polite word for temperamental POS that finds any excuse not to work right at best of times...
Added to that, even if the thing started and ran like a Swiss watch for me, Im reticent about selling the result on to some unsuspecting Schmo who is probably going to be let down by it before getting a decent run out of it.

I might drag this one back up. Got this thread while googleing to find the valve clearances for one of these.

I have had a bit more to do with the Tecumseh Ultima ULT50 ULT55 motors now, so I thought I should post up some extra info.

I have had issues with carb mounting studs. Stripped out of the block. Not an easy fix, but do able.

The main issue I have found is that the elbow with built in primer does not seat on the face of the carb with enough pressure due to compression of the plastic over time from servicing and over tightening then the carb does not prime properly. The nuts that hold the elbow on bottom out on the threads. Hence you can undo the nut and the stud will screw out, meaning the carb is half on half off and its a pain.
The trick is to make sure the gasket is good. One cut out of a fresh bit of gasket paper with enough clearance around the heads of the mounting studs will do the trick. Then some thin 6mm washers on the studs to make sure the face plate clamps up to the carb tightly before the nuts bottom out.


You can buy new replacement Chinese carbs, Ive stocked up with a couple. But I have not had too many issues with cleaning out the originals as they are mostly plastic and it does not grow stuff like brass, alloy and steel. The clip on bowl type with the self tapper screw in the front. Care must be taken as behind that screw is a spring and a little plastic jet. Hands and knees searching type deal.
Ive heard of a few having the plastic stripped out where the screw goes in, just like on a LM/G4 2 stroke carb.


Ive fixed a few mowers with these motors and sold them on and the customers have been happy. Very willing and smooth running motor, just a bit heavy, they are a fair lump of motor and over complicated to work on. Geez getting the fuel tank off is a pain.

I have two here on commercial Victas at the moment, a 505SP and a 550SP. The 550 is good to go, the 505 has some internal issues I think, it appears that the governor is not working, something is wrong internally. It runs flat out and the governor arm never moves.
I picked up a base with a motor on it thats missing the cowl, so I'm going over it, if it passes the tests and runs right I will swap it out.

Probably should be working instead of posting up on here.
Cheers, Bob.

this is my wifes mower, she mows lawns for a crust, i have heaps of mowers this is the one< she recons, starts really easy, cuts anything, mulches anything (i made wood chips with it untill caught, 10 mins) only prob i had was last week when had to perform mouth to mouth on it, took her up a steep hill to mow a lawn got there the mower, in the back of the car, leaked fuel. no start primer air, took off fuel cap quick wipe lips on blow and prime starts great again, looking into an inline filter. I love the mower, dont have a bad word to say about them.
my 2cents worth .
my twin is better

Hello Rodeobob and Shaunw

These are very helpful comments.
I think the post demonstrates how prejudices are generally founded in personal experience.
It would appear that these modern Tecumseh engines were a good motor, but with their own
design & service weaknesses. Pretty much like all motors...

Sean, this Supaswift is one of the great lawnmower chassis designs.
[Very similar to the Rover Model 29 base]. The thin frontal area in the front safety skirt
meant they were great for shock absorbing under commercial contractor use. The Scott Bonnar
520/720 - in contrast - was a poor design for commercial use. Your wife knows what she likes;
and for good reason.

All very Ultima
-----------------------------
JACK

all really good comments for sure . i found they really are a tough engine too , had one last week told me got slower lost power then stopped , as usual it was checked and maintained perfectly .
so in front of the customer i checked the engine oil . stick was dry as uuum . it seized ! but when it got to me was free again so i topped up the oil didnt take much , only 550cc !!! and away it went and that was a year ago , serviced it twice since and only issues were as always the carby thing on them .
this type has the main jet similar to a quantum BUT at the top of thread is a small really tiny hole often missed its so small and when blocked it wont prime or will start and stall .
just a tip on that one .

,Dave

My 2 cents ...

Good engine. Terrible Carby.

I have 3 on the go at the moment. I don't even bother cleaning the carbs out anymore. I just replace them with new ones.

To combat the issue in the future I fit an inline fuel tap and explain it's use again and again and again when I sell it.

Pete.

I totally agree with you mate

You can get a brand new carby for them from the Philippines for about $12, or you could since that is where I got my last one from via ebay. Not worth your time and effort to pull the old one down and try and fix it, especially if you are doing it for a living.

Ok so im thinking theres some wires crossed here.

SeanW's wifes mower is not a ULT motor, its a TVS.
Vccomm, not sure you are talking about a ULT/VLV motor, Im just servicing one, came in to google the oil volume (and got this tread again) as Ive put 600ml in and its on empty, volume is 810ml. TVS motor takes 630ml.

Ihatewetsocks, are they all ULT's? Im a fan of new carbs on the TVS's as well, but the chinese quality is dubious. You have to watch the fuel inlet elbows, ive filed the carb mount holes across on a few so the inlet elbow would clear the block.