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Siro 30

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Iron man

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Hey guys, me and my son need some help pretty bad. Found a savage 25 in my dads old shed with a blue top motor that says siro 30. Got some nitro in it ... May be pretty old fuel... How do you tell if its bad ? .. Anyway I have no clue the idle, low, or high settings need to be on this engine ... Any help greatly appreciated. I can get it to bust off hanging from a rope so it doesn't just take off on me ... The motor spins up real high and when I pull the igniter off of it it cuts out right away... If I put my finger over the exhaust it really spits fuel out of the carb so I'm sure it's pulling fuel ... But can be a really hard start at times... Anyone please help .. PayPal reward fine if you get it going ... I just can seem to get it right
 

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I'd tear the engine apart and clean it, then seal it as you put it back together, get some fresh fuel, new glow plug, then try again.

Typically 4 turns out on the HSN and flush with the housing on the LSN with 1mm opening when you look down the carb for idle will get you in the ballpark. Sirio made some ripper engines and if you have good compression, you should be good to go for quite some time.

Post #5 on this thread goes over sealing an engine:
https://www.rcnitrotalk.com/forum/showthread.php?t=60832
 
Is it possible to put a carb on that engine that woulnt work with it ? It seems to be to rich and only with a half turn from all the way in on the LSN and still wont idle or even run very long without the igniter still on a new plug even and seems still to rich just from cranking.

and when I get the LSN to far in below 1/2 turn out, then the servo can't move the plunger at all ? Is that normal ?
 
I'd try some new fuel, if it was sitting in the shed with the truck, chances are it's bad. I'd also get some new fuel lines and spray some WD-40 in the carb while working the throttle, and into the engine while turning it over, this'll help get any gummed up fuel out. The best way to clean it though, would be a full tear down like Olds suggested.
 
Ok, so I went out and checked out the idle settings... well 1/2 turn out on the idle screw ( please verify I have the right ones in the pictures ) and the truck still busts off strong enough to spin the tires.

I took some pics looking down with the screw all the way in compared to all the way out and I dont see anything changing inside... do you guys see something different between the two pics looking down the carb ?

Picture of the screw all the way out matches the last picture 362.
Second picture of the screw all the way in matches the 3rd picture looking down in the carb.

Is there something in the carb thats potentially broken ? fixable ?

thanks guys !!!!!
 

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If the carb is staying open that far with the screw out like that, your linkage isn't closing it enough. Either the trim on the trx is keeping it open, or the linkage has to be adjusted, I'd check the trim first.
 
? I'm really confused now ! .. Is the idle screw adjusting the plunger distance on the top side in that pic ? ... or the little disc looking piece on the bottom of the pics ? I've had the plunger piece that the servo controls in/out/and trimmed all over the place. I had what I though was it all the way touching that disc piece on the bottom and it still started up running the tires.....

In the pictures I dont have the "plunger" in any particular position... I thought I was looking for a change in the disc on the other side that the little needle slides into? I dont see it moving but should I be looking the other way ?
 
problem I'm having is...my carb doesn't look like this !

I read it already, but its not clear since mines different.
 

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mine looks like this....



so does turning the idle adjustment MOVE THE DISC ? ... or MOVE THE PLUNGER ? ... or neither ? .. both ?
 

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Disconnect the carb from the linkage, then push it the slide (plunger) with your finger until it stops. If you still have a huge gap, that would suggest your idle or LSN is way out of whack. Back out the LSN completely and take it out to rule it out, then back out the idle screw until the slide moves far enough to leave a 1mm gap as suggested. It should slide further in I would think, something is stopping it on you.

If this lets you lessen the gap, then do so until your near 1-2mm. Then, while pushing the slide (plunger) part in until it stops, screw in the LSN until you feel resistance. This would mean it's now hitting the LSN seat in the disc. Then I'd back the LSN out a few turns.

Then turn your radio on, set the trim to 0 for throttle/brake, then adjust your linkage at so that at idle (no trigger, no trim), the slide (plunger) has a bit of pressure holding it at the 1-2mm gap via a spring on the throttle wire.

The disc shouldn't move unless you have a 3 needle carb, which you don't.
 
Good catch. The angle it's at makes it a slide.

I agree, disconnect the linkage and slide it in and out to make sure everything is traveling smoothly.
While pressing it in, adjust the idle screw to make sure it's working properly. If not, it's possible it may be out of its track.
 
THANKS for all the help guys.. I ordered some new fuel now I'm just waiting on it in the mail....

The slide is NOT smooth at all and sticks... especially when you are not pushing straight on the screw part.. pushing out on the "limb" sometimes it wont move at all ?!... WD40 or liquid wrench best ?
 
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Iron man said:
THANKS for all the help guys.. I ordered some new fuel now I'm just waiting on it in the mail....

The slide is NOT smooth at all and sticks... especially when you are not pushing straight on the screw part.. pushing out on the "limb" sometimes it wont move at all ?!... WD40 or liquid wrench best ?
Click to expand...

Either or should work, I would pull the carb off and take it apart and clean it the best you can. I would probably use after run oil though to lube it that way if it gets in the engine it won't hurt it because after run oil is supposed to get in the engine.
 
My son got really disapointed because I couldnt make it go !... lol so I went an ordered an ebay traxxus 3.3 1/10 used but in good condition.. ( item number 150970467709 )

Assuming truck is in good new like shape, how would a stock 3.3 compare to this older savage .25 with the .30 siro motor in it ... I think this older truck had a 3 speed upgrade on it too with all steel parts so I'm really curious to see how it matches up with the 3.3.

thanks again guys.
 
Hey Ironman. I have a nearly new parts engine with the carb, crank, case and cooling head for that engine. If the carb is trashed shoot me an offer for it and I can drop in the mail for you. I had the engine in a T-Maxx and split the connecting rod so it is basicly whole engine minus piston and sleeve.
 
WOW ! it runs ! man does it run !! ... after breakin, first good hit of the throttle and I twisted the hex nut in the rear rims !! ... lol.

can't wait to see what it can really do .. thanks for the help guys !
 

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