Oil Injection - 89' Yamaha Excel

BigNiner19

Petty Officer 1st Class
Joined
Jul 1, 2006
Messages
234
What would be a good way to know for sure that an oil injection system is working (Other than keeping an eye on the reservoir with oil in it).

I had the cover off the front of my motor with the carbs exposed and could see fuel dripping out. I know, carb kit is coming and will be done. However, the more alarming thing is that this fuel flowing out of the carbs is clear, no oil mixed in with it yet? Does the oil mix in with the gas somewhere else or how does that work?

Definitely do not want to be running a motor with no lubrication, so I'm trying to confirm this now.

Here is a video link where you can see the fuel leaking out.

http://www.youtube.com/watch?v=ouaQGpmpE-Q&feature=youtube_gdata_player
 

noelm

Senior Chief Petty Officer
Joined
Mar 8, 2005
Messages
761
Re: Oil Injection - 89' Yamaha Excel

Yamaha mixes the oil after the carbs, so no oil in the carbs! but buy a manual just to be sure on how to fully test the motor, and for future repairs/maintenance.
 
Joined
Oct 28, 2010
Messages
923
Re: Oil Injection - 89' Yamaha Excel

Here follow these instructions. Disconnect the throttle arm on the oil pump, don't lose the cotter pin, get a portable 50:1 mixture of gas/oil, run @ 1500 rpms for approximately 6 minutes. You should know that this test is for Yamalube oil only (yes their is a difference in oil) the temp of the oil should be at least 86 degrees. Once completed find your oil pump ID mark (on the oil arm stamped) and compare. Your going to pick one oil point (nipple). I have never seen one fail. These are minimum specs.

oil_test.png
 

199675hpforce

Petty Officer 1st Class
Joined
Feb 27, 2004
Messages
299
Re: Oil Injection - 89' Yamaha Excel

I just did my 90hp my carbs were pretty clean and really did not need any attention. However the fuel pump did and gasket behind that with little center hole. When you take carbs off you will then see where oil comes out right behind carbs kind drips down with gravity and air rush from back butterfly pulls it in. A faulty fuel pump diaphram will load up with fuel on lower carb is there alot of gas in plastic air cleaner housing. Bad reeds will make fuel go out carbs instead of in. But your motor sounds better than mine at idle humm. From what I gather Yamaha oil injection is second to none and hardly ever fails. If in doubt you can always dump oil in tank maybe go 100 to one and play around or do test above and get container with 50 to 1 oil mixed then it's ok to disconnect oil injection. My motor is smoking pretty good so my oil system seems to operate. Curious why Yamaha lube must be used for test. Is this oil thinner for injection than say Cabelas oil. I bought 8gallons of semi syn for $10bucks each i could return and get 3 yamaha lubes
 
Joined
Oct 28, 2010
Messages
923
Re: Oil Injection - 89' Yamaha Excel

. Curious why Yamaha lube must be used for test. Is this oil thinner for injection than say Cabelas oil.

The reason that Yamaha oil is used is because all manufactures oil is far greater than cheap oil. I am not saying that semi syn is not quality oil I am just saying that from the price you paid, it is inferior to Yamalube. Conventional two strokes, oil injected or not, mix with the gasoline. Gas is a solvent, so a portion of the oil is washed off by the gas. Yamalube (and all other manufactures oil) stand up better to this because of the detergents. I not saying you have to run Yamalube but I would recommend using a manufactures oil whether it be Merc premium plus (or even the quicksilver brand), XD30/50, or Yamalube. In some cases shops will sell bulk oil where you bring in your container and it is dispensed at a reduced rate. Cheaper for the customer and the shop.
 
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