# Priming Oil Injection



## Cander_7 (Sep 13, 2017)

Thought I might get some good advice on if I need to prime an oil injection pump. 

I bought a 99 30hp Yamaha and had it shipped to me. The guy a bought it from packaged it really well. My question is do I need to prime the oil injection pump? The motor was running before he crated it. If I need to prime it, how do I do it?
I appreciate any input.


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## Guest (Jul 21, 2018)

I reccomend getting a FSM and follow the procedure for priming. It’s as simple as disconnecting the linkage, setting pump to w/o oiling, loosening the bleed screw and purging. You’ll want to run a 50:1 premix fuel until you are sure it’s consuming oil. Hope that helps.


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## RunningOnEmpty (Jun 20, 2015)

I always run 50/1 pre mix in any 2 stroke that's been sitting. A little double oil won't hurt. My old yamaha 30hp manual recommends it as well. That 30hp yamaha is on the top of my favorites list. I'd give it all of the good stuff including ring free because they are getting very hard to find these days.


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## Guest (Jul 21, 2018)

RunningOnEmpty said:


> I always run 50/1 pre mix in any 2 stroke that's been sitting. A little double oil won't hurt. My old yamaha 30hp manual recommends it as well. That 30hp yamaha is on the top of my favorites list. I'd give it all of the good stuff including ring free because they are getting very hard to find these days.


This, can’t go wrong with the ring free! Great stuff!


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## Cander_7 (Sep 13, 2017)

Thanks guys!

So if I run the pre-mix and then verify it is consuming oil from the tank does that mean my oil injection is functioning?

Another thing...previous owner has drilled (8) 3/8 holes in the air box. Should I get a replacement air box? The motor came from high altitude.


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## Guest (Jul 21, 2018)

If you run premix and it’s consuming oil from the tank then it’s safe to say system is working. You should crack the bleed screw to burp any air anyways. The pump itself relies on the oil for lubrication. As far as the airbox cover goes, I’d run it and see what it does. If from high altitude, I’d imagine different carb jetting???


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## Cander_7 (Sep 13, 2017)

Could you elaborate on how jetting for high altitude vs sea level affects the fuel/air ratio. Could I damage the engine running high altitude jets at sea level?


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## Guest (Jul 21, 2018)

The air at altitude is less dense. It may be jetted on the lean side for sea level operation. Look up the standard jet size for your engine and remove your high speed oriface and compare the numbers. Most outboards are tuned from factory to run at sea level. Yes, if it has been jetted to run at altitude/ thin air and you run it at sea level with this jetting you might be running it too lean and cook it!


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## RunningOnEmpty (Jun 20, 2015)

The wrong fuel mixture will burn hot and damage the pistons. You need to run the 102 main jets 
https://www.boats.net/product/yamaha/6J8-1492E-51-00?ref=fed66f39f462e47f5c37de3887bc8d57e2e54786
The holes in the air box shouldn't be a problem. This is how I ran my 30hp after installing 40hp carbs and a bunch of other things. http://i1262.photobucket.com/albums...30hp/WP_20150923_18_49_56_Pro_zpskilbme64.jpg


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## Cander_7 (Sep 13, 2017)

RunningOnEmpty said:


> The wrong fuel mixture will burn hot and damage the pistons. You need to run the 102 main jets
> https://www.boats.net/product/yamaha/6J8-1492E-51-00?ref=fed66f39f462e47f5c37de3887bc8d57e2e54786
> The holes in the air box shouldn't be a problem. This is how I ran my 30hp after installing 40hp carbs and a bunch of other things. http://i1262.photobucket.com/albums/ii617/blindshot75/Yamaha 30hp/WP_20150923_18_49_56_Pro_zpskilbme64.jpg


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## Cander_7 (Sep 13, 2017)

RunningOnEmpty said:


> The wrong fuel mixture will burn hot and damage the pistons. You need to run the 102 main jets
> https://www.boats.net/product/yamaha/6J8-1492E-51-00?ref=fed66f39f462e47f5c37de3887bc8d57e2e54786
> The holes in the air box shouldn't be a problem. This is how I ran my 30hp after installing 40hp carbs and a bunch of other things. http://i1262.photobucket.com/albums/ii617/blindshot75/Yamaha 30hp/WP_20150923_18_49_56_Pro_zpskilbme64.jpg



Do you think it is possible to remove just the bowl to access the jets? Or do I need to remove the whole carb?


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## RunningOnEmpty (Jun 20, 2015)

Boatbrains said:


> The air at altitude is less dense. It may be jetted on the lean side for sea level operation. Look up the standard jet size for your engine and remove your high speed oriface and compare the numbers. Most outboards are tuned from factory to run at sea level. Yes, if it has been jetted to run at altitude/ thin air and you run it at sea level with this jetting you might be running it too lean and cook it!


Sea level requires more fuel because the air is more dense. Same thing on very cold days.


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## RunningOnEmpty (Jun 20, 2015)

Cander_7 said:


> Do you think it is possible to remove just the bowl to access the jets? Or do I need to remove the whole carb?


You have to pull the carbs. the jets are screwed into the carb body. It's very east to do, but be very careful with the jets. You need a flat head screw driver that's a perfect fit or the slot in the jet will strip out super easy. I learned how to remove them when they get destroyed and seized.


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## RunningOnEmpty (Jun 20, 2015)

This is a picture of where the main jets are. I was using PB Blaster with a little bit of heat and the little easy out worked great. A certified Yamaha tech said it couldn't be done LOL
http://i1262.photobucket.com/albums/ii617/blindshot75/Mobile Uploads/20150129_165014_zpspfjtkjw1.jpg


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## Cander_7 (Sep 13, 2017)

RunningOnEmpty said:


> You have to pull the carbs. the jets are screwed into the carb body. It's very east to do, but be very careful with the jets. You need a flat head screw driver that's a perfect fit or the slot in the jet will strip out super easy. I learned how to remove them when they get destroyed and seized.


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## Cander_7 (Sep 13, 2017)

RunningOnEmpty said:


> This is a picture of where the main jets are. I was using PB Blaster with a little bit of heat and the little easy out worked great. A certified Yamaha tech said it couldn't be done LOL
> http://i1262.photobucket.com/albums/ii617/blindshot75/Mobile Uploads/20150129_165014_zpspfjtkjw1.jpg


Thanks for the info...I'm anxious to get this motor on the water, but don't want to damage it. Took me awhile to find the motor.


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## Cander_7 (Sep 13, 2017)

Boatbrains said:


> If you run premix and it’s consuming oil from the tank then it’s safe to say system is working. You should crack the bleed screw to burp any air anyways. The pump itself relies on the oil for lubrication. As far as the airbox cover goes, I’d run it and see what it does. If from high altitude, I’d imagine different carb jetting???


Thought I might define high altitude...3000-4000ft


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## RunningOnEmpty (Jun 20, 2015)

I got tired of the high prices so I built one from parts. I know those motors inside and out now. I got carried away with high performance mods. I managed to get just shy of 40 mph out of that little motor until the crank bearings failed when I hit bottom.


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## RunningOnEmpty (Jun 20, 2015)

Install new spark plugs and run it. If it runs good and the new plugs have a tan color it's good to go.
I had to play with different jetting way too much because of the mods. Pain in the ass after awhile!


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## Cander_7 (Sep 13, 2017)

RunningOnEmpty said:


> Install new spark plugs and run it. If it runs good and the new plugs have a tan color it's good to go.
> I had to play with different jetting way too much because of the mods. Pain in the ass after awhile!


Good tip...what will the plugs look like if it is too lean? How long and hard do I run it before checking the plugs?


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## RunningOnEmpty (Jun 20, 2015)

I always checked the plugs after getting home unless I had just made a huge mod. I ended up with 50hp jets in my 30hp and my plugs were still borderline lean looking. Black plugs are too much fuel, tan is perfect and anything lighter than tan is lean. These were my final tune and they look very clean because of the full synthetic oil. http://i1262.photobucket.com/albums...oads/WP_20151013_19_35_12_Pro_zpsqws7h5ee.jpg


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## Guest (Jul 21, 2018)

I’d check to make sure it wasn’t jetted for high altitude if it were mine. The time and money involved is way less that a stuck/ melted piston! Chances are it is stock, but I personally wouldn’t risk it over a couple hrs to verify.


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## Guest (Jul 21, 2018)

RunningOnEmpty said:


> Sea level requires more fuel because the air is more dense. Same thing on very cold days.


Exactly what I said, only from the other perspective lol!


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