wrong oil

[Vmosheen]

Howdy, I'm new to the forum and also a new vmax (83') owner. Upon inspection of my sled, I noticed the oil res. was low. Maybe a quart and a half left. Also oil warn light would glow. So my buddy had a gallon in his garage that he swore was ok for snowmobiles. The product was West Marine 2 Cycle TCW 3. After the sled ran for about a minute it died. Both plugs were wet fouled. I then emptied the res. with transfer pump, and thats where I'm at now. Does anyone know what to do to run the rest of that oil out, or should I fill it with Yamalube and see if that corrects the problem.

[vmax-540]

You should be OK just fill it with Yama-lube or what ever oil you want to use.You can take the oil tank off and make sure you drain it all out , but you really don't need to ,that oil shouldn't hurt anything.I don't think that oil is what fouled the plugs in the first place . What I would do is ,fill it with what ever oil you want to use , replace the plugs , start it up and pull your oil cable to the wide open position , just pull the cable apart at the adjustment and let it idle until you see oil going into the oil lines just before the fuel pumps and you should be OK.

[Vmosheen]

Well, the oil problem is solved, but now I see that I might have one bad fuel pump. I can visualy see gas just barely trickling through the fuel line. I have not been able to open the sled up at all since it's been so warm here and the snow is gone. When I test drove the sled it ran well. The engine idles O.K but when you give it throttle it cuts, then idles again, almost like air in the carb. Anyway I'm super stoked to ride this thing as soon as snow hits, just want to work out cobwebs. Thanks.. P.S This Vmax has 1628 miles on it and the engine has not been messed with, its all original

[vmax-540]

Sounds like you got yourself a great sled, It's not every day that you find a sled that old that hasn't been apart.I think if it were me I would rebuild both fuel pumps and replace both pulse hoses just for safety sakes, you can use rebuild kits for the Mikuni duel outlet fuel pumps , they are a lot cheaper then getting anything from Yamaha,as Yamaha fuel parts are expensive good luck , and I know that you will enjoy that sled!

[Vmosheen]

Well the problem continues. Went out this morning, sled started on third pull, reved fine, perfectly responsive, dropped to idle pinned at 1500, reved fine some more, let idle. After about a minute and a half the sled dies. Now it fires again and dies right away. Now it becomes a real chore trying to start it again. If it starts, it runs real rough and out of time. After a bunch of tries, and an occasional backfire I gave up. This sled ran great two weeks ago when I picked it up. The last owner cleaned the carbs, changed gearcase lube, and flused the radiator. I can tell the sled runs perfect until it slightly warms up. Anyway, I guess if it were snowing I'd be more bummed. Sort of!?

[8R9SRX]

have you been just starting it and just letting it idle and the ocasional blips with the throttle. just wondering if you got a fouled plug from not letting it run hard. change the plugs and run it around the yard, if you got the room.

[vmax-540]

I agree it sounds like it is flooding, you said you thing that the fuel pump may be bad, well you maybe right as a cracked diaphragm can let gas get sucked back in the engine thought the pulse line. What you need to do is change the plugs get it started and drive it and let it clean out,but I think you also need to start from scratch and pull the carbs off and check them out ,check the needles & seats, float heights, choke cable adjustments, synch the carbs ,and check the fuel pumps, that sled is 23 years old and somethings may be getting hard or starting to crack. I have seen a few sleds with cracked diaphragms act this way,save your self a lot of head aches and check these things out don't leave anything to chance.

[Nye Racing #13]

I only use Yamalube and I unhitched the oil pump.I have premixed my Vmax since the early 90's ans have never had a problem! Yamaha Factory rep told me to premix.

[opsled]

Hi, I agree that you probably have a fuel problem and that your engine is getting way to much of it for some reason. A quick look at the plugs will tell the story if they are wet its a fuel issue if they are dry you have another problem. I agree with the others that you should go through the carbs and check the fuel pumps. My experiance with fuel pumps is that the diaphrams can leak and if they do the engine will draw fuel through the pulse line and flood that cylinder however it is not that common unless the pumps have been sitting dry for long time. I see more pumps that won't pump well because they are dirty and varnished from sitting with old fuel in them. Chances are if the carbs are dirty and varnished so are the pumps. Also the chances of both pumps going bad and leaking at the same time are not very good so if you are having a flooding problem on both cylinders the pumps are probably not your problem but they should be checked just to make sure. I don't know how well you know the guy that cleaned the carbs but I have seen alot of burnt up or bad running engines that have just had their carbs cleaned. Cleaning carbs is not rocket science but if you don't know what you are doing you can do more harm than good. I know alot of guys that think blowing out the main jet with some carb clean means they cleaned the carbs and there is alot more to it than that. Even good mechanics can make mistakes so never assume they have been done right just because someone says they have. I second guess myself and double check my own work all the time and I am not ashamed to admit that I have cought myself making mistakes and I know I will make more in the future. An old guy told me " You show me a man that doesn't make mistakes and I will show you a man that doesn't do anything" so it pays to double check just to make sure. Your carbs have 4 circuts (choke, idle, main and power) and there are air and fuel passages for all of them. All the passages need to be clean with no buildup of varnish for them to work right. They are also jetted different from right to left with the left being one step richer on the power jet. The carbs should be stamped 8U9-00L and 8U9-00R on the front side of the choke plunger boss. R is for right L for left and 8U9 designates 83 Vmax. The only other thoughts I would have that havn't been mentioned by others is to check choke the cable routing, the rubber tips on the choke plungers and make sure the guy that did the carbs didn't install the float tabs in upside down. I've seen cable routing cause the choke plungers to not seat properly and the rubber tips can crack which can cause the choke circuit to be dumping some fuel all the time although it is not a common problem. If the float tabs are not in correctly the needle valves might not be closing. One last thing that is unrelated to a flooding problem is the fuel transfer hose for the power jet circuit. Make sure that the line is the correct size and that they are the same from one carb to the other. I will only use Yamaha line for these as it is the correct size and the size and lenght of the line will effect how the fuel is drawn up to the outlet.
Good Luck and Merry Christmas, Phil (opsled)

[snowball_1]

Check the choke (enricheners) first. The engine needs a richer mixture at first, which is why it may run fine at first, but as it warms, it dies from the overly rich mixture. Check that the enrichener plungers are closing when the choke is turned off.