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Polini Thor fuel starve


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Hi there. I am having some issues with my polini thor 100. I've done about 30 hours on it since acquiring it second hand, previous amount of hours were unknown. 

Brief history:

Was prone to fuel starving (presumably) if not primed correctly. Had been flying a revo 2 26m wing which wasn't too demanding on the motor so this never starved, then a 24m gtx which had no issues, started flying an itv wing and I had a load of problems, mainly maintenance issues all of which are now remidied with a carb rebuild, new gearbox gaskets and some bearings. 

Went for the first flight on 6 months and the motor cut out just after climbing altitude, the motor had been up for 20mins. 

Can someone advise me on how the fuel system should be setup, there's a kink just before the prime bulb which may be the root of my problem, is there any reason to not replace the fuel lines to the same thick gauge that's used above the prime bulb? There appears to be thin tubing, then thick tubing after the bulb. Also is the high point a problem? Air often seems to get trapped in their however this may be due to restricted fuel flow because of the kink. 


Any help or pictures of setups would be greatly appreciated, thanks. 




Edited by Olz
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Somebody has moved the primer bulb to a position where it is easier to reach. I would replace all those old fuel lines and run them so that the bulb is just inline vertically between the tank and the carb. Also, it needs clips on all the joints to prevent air getting in. You might also find a filter on the end of the pipe inside the tank - it works as the clunk. I would replace that as well (and the fuel line inside the tank, or at some point it will snap and fall off!).

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Ahh okay, it did seem a bit odd that there was some sort of breather on the tank. As it transpires the pistons holed, so I shall replace all the fuel lines and get the cylinder head rebored and new piston.... May be after recommendations for other motors! Thanks for all the help guys! 

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6 hours ago, Olz said:

As it transpires the pistons holed, so I shall replace all the fuel lines and get the cylinder head rebored and new piston.... 

IMO i wouldn't rebore unless liner is scratched or marked, all depends on how long and hot it was when damage occured, plus if you struggle getting a new piston just get old 1 repaired, i have done a few which are still going strong after numerous hours use, sort out your fueling problems and then should get many hours flying it.

just found pictures last Polini piston during. ALIM0243.thumb.JPG.6325febfe5dccda176fed9ed60ba8cc7.JPGNot ideal finish but was heavily detonated middle to edge as seen in above picture, and finished article below.ALIM0245.thumb.JPG.989704e2780ffb7cb2f04781ff3edbdd.JPG

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