May I ask where you got your 46g inlet spring. Having the same issue but can’t find a 46g for the HB series carb.
Thank you!
1 Like
I have ordered from EC carburetors:
https://www.eccarburetors.com/search.html?k=Tillotson+inlet+spring
Be advised that you’ll need to richen the carb when running the heavier springs in order to stay within EGT range. Also, be sure you’re replacing the gasket/diaphragm kit on a regular basis, as those can contribute to the issue when worn.
Lastly, be sure not to “creep” on throttle too soon. Altering my technique fixed 80% of the issue for me, as I had a tendency to modulate throttle (too) early from my days in Stock Honda.
1 Like
Forget the 46gr, go straight for the 48gr, hands down wayyyy better!!
I don’t know if Tillotson makes a 50gr, but if it did, it would be ideal as once in a while you will encounter a turn where even a 48gr isn’t enough, right now the best solution once you have the 48gr on is to shift from 2nd to 3rd as soon as possible, in other words carry enough speed coming out of the corner so you only need to stay in 2nd gear very, very shortly; as soon as you go onto 3rd the engine response is perfect and you can stretch the 3rd gear as long as necessary without any issues (although short shifting as a general rule is the way to go with this engine.)
And as mentioned, replacing the diaphragm as soon as the engine doesn’t perform as it should.
One advantage of the SSE 175 engine is that it runs perfectly well on pump gasoline. I filled the tank with Premium and oil and went to Adams last Sunday. It had no problems with detonation or power loss, and the spark plug stayed clean the whole day. Given how much fuel a shifter uses (20 MPG or worse), I think it’s a big selling point to use a fuel that costs less than five bucks a gallon. In CA we don’t even have 93 AKI/98+ RON premium gas, it’s 91 AKI with no information on RON.
This is another engine that supports the #GetTheLeadOutOfKarting campaign.
2 Likes
I love the SSE 175, Fast, Reliable, and Low Maintenance!
On top of that you can have an electric start if you want, IAME has thought of everything!
TM has had e-start since the K9ES. Welcome to the party.
1 Like
I know, I know, but the R1 seizes after 8-9 hours every time, very unforgiving engine…
Apples to oranges comparison. The TM R1 is in a higher tune state than the ES model, which is tuned to go longer between rebuilds; pretty much the same as the SSE & stock moto (Top end @ 100-140 L/26-37 gal; bottom end @ 400-440 L/105-116 gal).
There’s a logic break for me. If there’s a fundamental problem with the use of the 42g spring in the HB-15A, why does Tillotson persist with it in the carburettor’s base setup? Also, is this problem apparent with the SSE or just the base SS derivative of the engine (since Europe moved away from the Dellorto to the Tillotson). Presumably IAME and Tillotson spent a great deal of time working up the HB-15A for the release of the SSE in the USA - wouldn’t this problem have jumped out in testing (and then subsequent race use) if it were a systemic issue?
That’s a very good question, and as far as I know a 46gr or 48gr spring is what everyone is using here in Europe.
I’ve no idea why Tillotson is selling the carburetor with a 42gr, but it drove me crazy for quite sometime.
And by the way, the Dellorto was working fine, nothing wrong with that carburetor, Ok the Tillotson makes things a bit easier but…
I guess IAME decided to use Tillotson for all their engines, even the 175 automatic and shifter.
I agree, apples and oranges 
What’s the perceived advantage with the Tillotson setup? Diaphragm carbs make sense in aviation applications because the active feed provides fuel/air irrespective of directional/gravitational orientation, but I don’t see what they bring to the table in an application where physical orientation is static, as with karts. The externally accessible idle air, & low & high speed fuel feed is really nice (something I wish std bowl carbs could have), but the diaphragm maintenance/replacement intervals are short.
You said perfectly, the Tillotson makes things a lot easier, especially during a racing weekend, the 175 demands perfect tuning, with the Tillotson you don’t need to spend the day changing jets from early morning, to midday, to late afternoon (imagine a team with 15 drivers, 15 engines, 15 Dellortos that need to be tuned, that’s how it used to be.)
The Tillotson simplifies things, but having said that, is a diaphragm carburetor the best choice for a shifter kart engine? Dellorto is a damn good Carburador for shifters.
And yes, diaphragm carburators need maintenance quite frequently, but especially when being used with the 175, as this engine is very sensitive, a lot more sensitive than an X30 (125cc)
It would be interesting to find out why IAME decided to go for the Tillotson, although it seems a bit of a business decision.
Where did you find find the data on the rebuild intervals for the ES?
A top end will last a lot longer on a ES than KZ10B/C or R1, but 30L vs 140L for an engine with slightly different port timing is surprising.
I’ve heard from the IM guys that some customers have run it for a full season on 1 top end, but probably not recommended.
I probably have about 100L on my top end but I feel like that’s pushing it, though it still has great compression and easily pulls up to 14500. I have my squish set at 0.039 and advance at .066 as well which is closer to the R1 guidelines.
They’re old figures, first published back when the K9ES was first released. No doubt, they’re probably the extreme duration. I verified them with IM-USA. The K9ES has a 22mm crank bearing (K9 A/B/C series is 20mm), rev limiter, & different cylinder with no boost ports. For the KZ10 generation, TM made the 22mm crank bearing standard across the entire line; the ES still has the rev limiter, but has the boost-ported cylinder like the rest of KZ10 series. The rev limiter is probably the main reason for the service interval differences.
Your info is consistent with what I’ve found. Starting with the KZ10B TM switched to the 22mm crank pin as you said. I think the recommendation with the ES is 16:1 rather than 20 - 25:1 premix which also helps a bit.
Forgot to mention I swapped the Selettra rev limited ignition for the traditional PVL ignition used in everything from the K9 to the R1. From what I could see in my Mychron RPM trace was the Selettra was limited to 13800 RPM. Now I have the convenience of electric start with no rev limiter. Some initial teething issues with starting as I believe the stock ES ignition is able to generate a spark at lower cranking RPM, so I needed a different battery solution to get the starter turning a bit faster.
By boost ports you’re referring to the additional exhaust ports on either side? From the info available and pics of my cylinder I see the same number of transfers.
The recommendation I got from Michael V. is 6% oil (~16.67:1) break in, 5% (20:1) normal op. Remember, you’re running leaner with more oil in the mix.
Yes, the extra exhaust ports are absent in the K9ES, but they are present in the KZ10 ES. Transfer ports shouldn’t be different.
If you don’t mind me asking…you said you are from Spain correct? Aren’t the 175s running with Dellorto 36mm in Europe? Why would you run a EU-spec 175 with a tillotson? Ease of use for jetting changes? Also, do you run an ignition limiter (14K) or no limiter (17K)? The US version of the engine is not the same, so can’t be compared exactly to the EU-spec unit but I always thought the dellorto was pretty much the only choice over there
Hi Andy
I’m sure Peter will be back to you with his journey, but having just acquired a 175 SS in Australia (not the SSE, so I get an electric start), they now come standard with the Tillotson HB-15A and a Selletra ignition. As far as I know, the Tillotson has been used as OEM for the last two years or so. One can still order the 36 mm Dellorto, but it’s a special.
On max RPM, as far as I know, it’s limited to 14.1K (but I haven’t gone that far yet).
I’ve chosen to start with the Tillotson and rather hoping it works for long/road circuit running, but the jury is still out (at least for me). I do intend to also test the 36 mm Dellorto and see how they compare (particularly on a track like Phillip Island, which is very tough on kart engines given it’s fast and has relatively long sections of WOT - only 10 days ago we had three Stock Hondas seize (thankfully not mine), plus some DEAs; it was cold through and perhaps some cold seizes).
Back to my 175 SS and HB-15A experience so far, there have been some early tears.
I broke my engine, and new kart build, in at our local sprint track (Geelong, near Melbourne). All good so far, ran great with massive torque compared to my Stock Honda (but didn’t take it above 13,000 rpm), love big time the electric start, but found it very hard getting the water temp up into the desired range (say north of 50 degrees C) , even with the three-way thermostat bypass (which also comes as standard along with the mother of all radiators; which I may need to change for our winter months).
Then off to Phillip Island for its for test long/road circuit run. Changed sprockets to 20T on the engine and 21T on the rear. Low speed needle at about 1.30 and High at 1.50 (major error) 
Got around the first lap and into the main straight, and probably had my first clue that I was too lean. I short shifted from 5 to 6 and it seemed to bog, so backed off and continued (idiot, I should have come in). Got around to Siberia (T6) and coming out (I think in G5) hit about 140 km/h (87 mph) at 12,000 rpm and around I go with my first seized engine in my five years of karting. EGT had suddenly spiked to 719 degrees C (1,326 F).
Some photos below (yes, I’ve taken the plastic wrap off the pipe, this photo was when it was first delivered, the others are immediately after my tears). Maybe it’s part lean and cold seize - I should know more late this week once my engine builder has had a look. I was not happy with myself as I was warned to add at least an extra 30 minutes beyond a sprint setting (say 2.15 to 2.30), but completely forgot.
I used Elf HTX 909 and ELF Race 102 (yes, it is happy with Premium 98 but I wanted to be safe, at least that was the idea). Oil ratio was at 20:1 (5%).
Anyway, testing continues. I’ll try and take it for a run at Winton next week and then back to Phillip Island. Interestingly, I chose the Formula K chassis like you. It felt great and very stable at Phillip Island (even on a very wide rear track for long circuit running - we go as narrow as 1270 mm, maybe shorter). Brakes seemed fantastic.
If I can offer some offer some generic advise…
It’s hard to blow up a motor by going too rich, if you’re unsure of where you are for jetting when you hit the track… keep richening it as you drive and observe how it reacts.
A quick tap on the airbox can give a clue as to what direction to head on jetting too.
Lastly, it might be worth lowering the pop off pressure for longer circuits to richen the fuel curve across the entire range.