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Discussion Starter #1
Ok guys here's the story. The engine as been rebuilt with all new parts. I drain the old gas in the tank. I clean and adjust the carb the best I can do myself, it took me 1 hours to make all the slides to open and close at the same time. I fill the coolant bottle and the engine with pre-mix 50-50 coolant\water! I put some oil down the cylinder, zip tie the throttle at WOT, kill switch off position and gas valve off position(don't wanna to start it). With the plugs still unscrew (less hard to pull[^]) I pull the cord to see if injection tubes will get some oil. It took me something like 20 minutes of pull and the oil as been just at the halfh of the length, except the middle cylinder, no oil at all in the tube! Did an oil injection pump can failed just at one tube? The thing is kinda weird cause when I did the rebuilt I make a special tool with a drill, makes the oil pump turning at correct speed while holding the lever at MAX. All 3 lines was pumping oil at same time! So now by pulling the cord the middle tube wont getting oil. Kinda weird!?...So I decide to make pre-mix gas and start the sled, this way I can check all the oil tubes after one tank. Someones told me to mix 40-1 and others 50-1, I decide take the middle and mix 45-1. I put 5 gallons in the tank (mix), and mark the oil tank with marker. Open the gas valve and put the plugs back. Choke on, it tooks 6 pull to start it up. Woo-hoo! Let it run idle for 5 minutes with the front of the sled raised and check for coolant level and leaks. Everything ok, even the exhaust temperature was the same at the output of the 3 cylinder, the middle little higher but ok. I pull the wire plugs off and on and check the engine rpm drop. All cylinder drop at the same RPM, so I found the carb sync for the idle was ok. With the engine warm, I go take a ride (1\2 miles). And I found major leaks of coolant while the sled was bogging down[V]. The temp gauge hit 180, so its little hot but nothing to hurt engine componants[^]. I found the coolant cap was leaking, change it for a brand new. Re-check the coolant and adjust the level. I make lot of plug chop. I was little sceptic with the pre-mix so I make severals plug color reading. (8 to 10 times) At many speeds but no WOT as the engine is new! The all times look perfect tan-brown color[^]. I go ride it another time, now, after 1\4 miles, it start to bog so bad. I put the brakes and open the hood, and let the engine ran, found nothing special. I idle bad, way too slow, but playing with the idle screw won't help at all, I try! If you let it idle, it won't die, the engine struggle to keep it running at idle, but if you hit the throttle it bog so bad, even if you try to pump the throttle or keep it at contstant place the engine will bog. It will still run but will bog! Did you think 5 gallons is ok for a WET tank? The gauge mark at the reserve level, I check in the hole and found enough gas. This gas pump was working great last year. Another thing is that when you hold the throttle at 1\2 and pumping it, the engine back fire in the center carb. Do you think that the engine could be fooled or what. I really wish I didn't broke something... I check the comp only with my tumb (I know its not accurate, but the gauge was at the shop) and as plenty of! Please guy tell me about your tips, or wha ya think could cause this... At the begginning it was running awesome, and now I can't make it to run at idle... 5 gallons of gas and 30 minutes testing\ridding is enough I thing, it should have still enough. I'm really confused...[V]
 

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Too much input. Your last question, I had the gas line in the tank break down including some black goop holding it in place. It clogged everything. Filter was a screen in the tank. The screen didn't help since the gas line itself broke down. Since then I have a high capacity gas filter between the tank and pump.
 

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Discussion Starter #3
when I clean my gas tank I check for that line and filter. They was in good shape... for what I saw! Did this hose in the tank should be loose or something is suposed to hang it firmly at the internal bothom of the tank?
 

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Sorta sounds like a pluged fuel filter or pump not pumpin good. After it bogs out, if you let it idle for a while will it run ok for a bit? if your premix and injecting oil it might be just getting really loaded up on you too. Running a tripple slow at stedy low throttle with double the oil is asking to get it loaded up. It doesnt hurt to braaap a new engine wot for 2 seconds or so once you've ran it a little, just dont ride it real hard.
 

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Discussion Starter #5
Originally posted by Boss302man
[br]Sorta sounds like a pluged fuel filter or pump not pumpin good. After it bogs out, if you let it idle for a while will it run ok for a bit? if your premix and injecting oil it might be just getting really loaded up on you too. Running a tripple slow at stedy low throttle with double the oil is asking to get it loaded up. It doesnt hurt to braaap a new engine wot for 2 seconds or so once you've ran it a little, just dont ride it real hard.
Yeah, its kinda weird cause the engine was running great and after that it start to bog like hell. the gas filter is new. Never think of that, but like you said maybee the engine was running great with pre-mix only, but when the oil pump as been bleed, it loaded the engine and making the bog issue. I will take the air-box off and see if the oil pump is working right!
 

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I would suggest pulling off the carbs and clean them up real good. Sounds like fuel starving issue. Take them apart and let them sit overnight in container filled with carb cleaner. Blow out the passages, etc. When carbs are off put the fuel lines to carb into a container and pull the engine over and see it you got fuel squirting out.
 

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A new set of plugs, and it will be fine. IMO!!

When I rebuilt my XLT 50:1 pre-mix plus the oil injection I went tru 4 sets of plugs within the first tankful.
 

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Discussion Starter #9
I check the plugs, they are all good. But it seems to be a firing issue cause I don't have spark on 3 cylinder (I check the plugs on another sled and they are sparking)...Now I'm very confused cause I check and measure all the firing componants with the owners manual and spec before assembly. Even the front and tail light didn't light when pulling the cord. I think the mag or cdi is broken.
 

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check the coil wiring on the pto side coil, Im always finding that set comes unhooked, and that runs right to the cdi
 

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if your oil injection system is completely unhooked, run 32:1...45:1 is just not enough oil and I would fully expect to see overheating issues. If the engine is brand new, do not use synthetic oil. It will not allow the rings to seat and you will have to re-hone the cylinders. Just so you know, the less oil that is in X amount of gas, the richer the engine will run (think, less oil = more gas in a set volume of liquid, and if you add more oil, then you effectively lean the fuel/air ratio because more oil = less gas in a set volume of liquid) Only thing is, leaning the mixture using oil is far less dangerous then leaning with simply less fuel, because the extra oil helps lube and cool things down. This is an old trick we use on the motocross bikes when racing in the summer....while the guys would be taring down the carbs changing jets on the hot days to lean out or richen the A/F ratio, we would simply be adding more oil or more fuel, works like a charm!! (we never changed the spark plugs heat range because motocrossers are WOT all the time, but in a trail sled you might consider 1 step hotter and plug read often!
 

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Discussion Starter #12
thanks for quick reply guys,I will start to check the cdi connection, I remember the connector was easy to slide together. As for the oil injection, it looks that the 3 lines have stop to injected for now. I'm sure that its about the oil pump shaft free play in the case. As I said in another post,I changed the crankcase and keep the less worn parts, and never check the shaft free-play, as the manual told to put back the old shims! I was pulling the cord with plugs removed and there was a decent flow of oil in the tubes, but it strangely stop to inject! Pretty sure the free-play was too big and the crankshaft stop making the oil pump to turn. I will work on it tomorrow after the job and tell you about what I found!
 
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