adam180t Posted April 9, 2022 Share Posted April 9, 2022 So i have a hpi trophy truggy 4.6 and i have recently rebuilt it run in and runs perfect cold to warm and goes fine at that point on quarter to half throttle as it warms up but once it gets hot and i go full throttle it goes fine till i let off and it dies cant understand it could it be the plug its a cold plug so mabee that could be why Quote Link to comment Share on other sites More sharing options...
Nitroholic Posted April 9, 2022 Share Posted April 9, 2022 There are a number of things that can cause this ...... 1) Idle setting. If the idle isn;t properl;y set, it can be 'holding' on the servo, so as you brake to a halt...the inlet closes copmpletely and the motor dies. Easy to check...just pop off the air filter, and power up the servo. Then brake. You will see if the throttle stays on the stop and maintains the required 1mm opening. 2) Fuel air/vapour locking. Check your fuel lines are in good order, and firmly sealed on the tank and carb. Make sure there are no kinks, and check if it is routed neatly and as far away from hot things as you can. Fuelling problems will be masked at higher throttle opening partly by tune...and partly because the exhaust is putting more pressure into the tank. 3) Glow plug could be starting to fail. That can cause all sorts of issues. Plug heat range should not really have issues only when hot. I would start with a thorough check over, and possibly renewal of the fuel lines. Can't hurt....and it's cheap to do. Also check the seal around the tank top while you are at it. If you have a spare glowplug...try it and see how that helps. Check the idle setting and the servo so it definitely stops on the stop screw. Don;t know how much use the motor has had..,.. but if its getting past its best..that usually manifests when the motor is hot, as the compression starts to fade. When its cold, its naturally tighter, so that hides it. Quote Link to comment Share on other sites More sharing options...
locky Posted April 9, 2022 Share Posted April 9, 2022 Does it start easily after it dies when it is 'warmed up'? Checked clutch shoes and springs and clutch bell? Checked idle gap? If it is hard to start but will when it is cooled down, then the piston/liner are probably worn. Engines should be tuned at normal running temps as tuning will be different when engine is saturated at about 200F. Try richen LSN and increase idle. Having a good spare glow plug will rule that out. Quote Link to comment Share on other sites More sharing options...
R46 Posted April 18, 2022 Share Posted April 18, 2022 First thing be increasing idle. Using a branded glow plug? How old is fuel an pecentage? Airfilter foams clean an not over oiled? Could have a partial airleak around neck of carb or back plate. Plugs 👍🏾 https://www.modelsport.co.uk/product/fastrax-platinum-glow-plugs-no5-medium-401882 https://www.modelsport.co.uk/product/os-no8-glowplug-medium-1762 Quote Link to comment Share on other sites More sharing options...
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