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| Engines Discuss engines |
Topic Review (Newest First)
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| 07-15-2016 09:00 PM | ||
| floyd |
Re: DA50R Over Heating Here's another interesting read on the subject. Cheers Floyd Two stroke engines are picky eaters. Change the oil/fuel mixture, fuel to air mixture, heat range of plug, type of gasoline, type or size of carb., exhaust system, geographical elevation, outside temperature, etc. and you need to re-jet the carb. Your engine has a main jet that the fuel mixture must pass through to be mixed at the right ratio with the air. Too much oil in the fuel causes the mixture to be thicker, which causes the air to fuel mixture to get way too lean. You thought you were adding more oil by using a thicker mixture. What really happens is that the mixture could not get through the main jet at a sufficient volume to lube the engine. You actually gave it less oil. It is like putting ten-weight versus sixty-weight oil in a drip oiler and still expecting six drops a minute from the same setting. You also starve the engine for fuel which also causes the engine to overheat. Kind of a double whammy. There was an excellent thread about 'extra' oil in a 2-Stroke engine and what it could do - the engine will run lean - this is NOT good for the engine - more oil (non-combustible) actually 'dilutes' the gas you are burning. Less gas and the same amount of air = lean conditions. |
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| 07-15-2016 06:35 PM | ||
| Mike Sebastien |
Re: DA50R Over Heating Quote:
If you read my link I gave earlier you would have answered your own question. At 30:1 and higher mix ratios the ring seat may carbon up and the spark plug. if it is a high compression engine such as a ZDZ engines which can handle the higher temps of premium gas this isn't a issue. For me as I said earlier I have had good results with premium Gas and a good non-petroleum based oil that doesn't contribute to the carbon build up. I have a ZDZ 160 with at least 100 litres of fuel through it and there is very little carbon build up on the piston crown. I wish AJcoholic was still around he would have provided a better explanation than I can. |
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| 07-15-2016 05:55 PM | ||
| allan980 |
Re: DA50R Over Heating I find this post very enlightening but I was wondering what is normal operating temp for these 2 stroke gas engines [roughly] thanks Al |
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| 07-15-2016 05:49 PM | ||
| floyd |
Re: DA50R Over Heating Well if it doesn't make a difference in how a motor will run then why wouldn't all the engine manufacturers just tell everyone to run 20 or 30 to 1 as a mixture to extend the life of the motor? Cheers Floyd |
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| 07-15-2016 01:06 PM | ||
| flytoit |
Re: DA50R Over Heating That is true / not a big difference and I for one am not sure of the effect . Further tho it would be a tad thicker and may affect the volume per stroke of the motor . Again just my thoughts and I wish everyone good running long lasting engines . |
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| 07-15-2016 12:55 PM | ||
| Mike Sebastien |
Re: DA50R Over Heating Quote:
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| 07-15-2016 12:28 PM | ||
| flytoit |
Re: DA50R Over Heating The way I see it ,the needle valve at a given setting lets in a given volume per stroke of the engine . Thus if that volume is mixed at 30/1 it will be less fuel (more oil) per the given volume than fuel mixed at 50/1 . Just my thought |
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| 07-15-2016 11:36 AM | ||
| Mike Sebastien |
Re: DA50R Over Heating Think of it this way. The constant in the ratio 50:1 or 30:1 is the amount of fuel. For example in both ratios we use 1 liter of fuel then add oil. In the ratio 50:1 there 1 liter of gas and 10 ml of oil. 30:1 would require 1 liter of fuel and 30 ml of oil. The amount of fuel is constant but the oil content changes and that's why u don't have to adjust needle valve, also why the engine doesn't run hotter. After you mix the oil total quantity of mixed gas for 50:1 is 1010 ml and for the 30:1 is 1030 ml. |
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| 07-15-2016 10:13 AM | ||
| Flypaper |
Re: DA50R Over Heating You open up the needle valve to get the right fuel air mixture. |
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| 07-14-2016 10:10 PM | ||
| Mike Sebastien |
Re: DA50R Over Heating Quote:
http://www.off-road.com/dirtbike/tec...ity-54169.html |
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