Precision Blend System Question

[dubber]

Gurus I have a 1990 225 2 stroke carb model number 225ETLD. I have questioned the oil injection system since I got it (from a donor blown up motor) and have been pre-mixing on a rebuilt motor for break in and also because I questioned it anyways.

I have ran the motor for a number of hours and I know that the onboard oil tank is not drawing down. I bought a new oil pump and was replacing it today when I decided to experiment with the old one. Observations;

1. With the old one on and all 6 outlet lines pulled I rotated the pump manually. Some oil would come out every now and again. Cannot say for certain if it came out all 6. The pump intake was still connected to the oil tank. I bled it as well. A few air bubbles came out but nothing major. I noticed that I had to spin the pump about 4 times before anything would shoot out. This was mostly repeatable about every 4 revolutions or so.

2. I blew into about 3 of the outlet lines that go up to the intake. I expected that they would blow free but none did. It was like blowing into a closed container.

My question is what I saw in item 1 with having to spin the pump so many times is this normal? For item 2 is this normal as well in that there is a check valve or something else putting back pressure on the lines? I would have suspected it was just atmospheric pressure as the oil intake is just behind the butterflies on the carbs.

Just want to know if I am on the right track or not changing the oil pump.

[ausnoelm]

Buy a genuine service manual, it will probably tell you how to actually test things according to the manufacturers recommendations, rather than blindly blowing in hoses and guessing, the Yamaha system is very good, and gives little trouble.

[dubber]

Thanks for the suggestion but hoping someone here has some insight into this.

[amahaork]

engine mounted oil reservoir filled by pump at remote reservoir mounted oil pump - is it works? once engine mounted oil reservoir getting filled, oil flows down to the engine oil pump, driven by crankshaft.
oil lines have check valves - do you have them installed?
do not expect oil squirt out of this pump. once system completely filled and free from air, constant flow of oil moved (pressed, delivered) to the carburetor. after long periods of storage, it is necessary to start and run on gas/oil mix 50:1 for at list an hour to purge all air to prevent damage. some hard core use constant gas/oil mix to addition to precision system to minimize damage during long *****ing or low rpm. no harm here, just check spark plugs frequently for carbon build up (if any), not only at the beginning of season. once you got service manual, you don't need this forum, only parts ordering.

[dubber]

Yes the remote oil pump is working. Check valves should be there. Other than the bleeder screw on the injection pump is there any other places to purge air from?

[amahaork]

it will purge itself during first time running on gas/oil mix, you definitely need to read service manual. you just have to be sure all oil tubes are filled with oil. I install clear tubing, chemical resistant, to make sure all air purged.

[dubber]

it will purge itself during first time running on gas/oil mix, you definitely need to read service manual. you just have to be sure all oil tubes are filled with oil. I install clear tubing, chemical resistant, to make sure all air purged.

I am hoping that if it is simple enough the steps could be posted so I could get this oil pump rolling again. I have bled the pump now with no more air bubbles coming else. What else is there to check/do?

[amahaork]

there is procedure to check oil pump output. it's required to disconnect oil link to pump lever and with working engine (on mix 50:1 for safety) collect oil output from some cylinder with pump lever manually to max. I never done this myself. check with your engine service manual.

[boscoe99]

I am hoping that if it is simple enough the steps could be posted so I could get this oil pump rolling again. I have bled the pump now with no more air bubbles coming else. What else is there to check/do?

Nothing more to be done.

If you want a measure of insurance just run on some premix for a bit of time while any air bubbles get bled from the oiling system.

[dubber]

Nothing more to be done.

If you want a measure of insurance just run on some premix for a bit of time while any air bubbles get bled from the oiling system.

Perfect. That is what I wanted to hear.

[dubber]

there is procedure to check oil pump output. it's required to disconnect oil link to pump lever and with working engine (on mix 50:1 for safety) collect oil output from some cylinder with pump lever manually to max. I never done this myself. check with your engine service manual.

A pumping test like that is simple and messy to do! It sounds like bleed the air and it works or the motor pops. I am going to roll with the pump replacement and keep pre mixing for now. Thanks all.

[99yam40]

If you mark and measure the amount of oil used while running the premix also then you should be able to see if it is using the oil in a proper ratio of the gas you use

[dubber]

If you mark and measure the amount of oil used while running the premix also then you should be able to see if it is using the oil in a proper ratio of the gas you use

Yes sort of though as the injection system is variable. This assumes running at a set rpm and a known ratio at that rpm. I am all over the rpm map when I run lol!

[bajakeith]

oil flow/rate

its variable on rpm and a very small amount to temp..but forget about the temp.......when you melt a piston on a two stroke its not due to no oil !!! but lean fuel condition (understand EGT) poor cooling is the main cause 90 percent of the the time..poor impeller install (very common),,over propping,,poor,bad fuel,improper timing (RARE),poor heat transfer from rings to piston due to cabon buildup...on a hot day slightly more oil is injected than say a cold day...NOT enough to make a difference to your motor...woo wo..sleeptime...night all...OUT!!

[99yam40]

Yes sort of though as the injection system is variable. This assumes running at a set rpm and a known ratio at that rpm. I am all over the rpm map when I run lol!

Yes but it will show that oil pump is putting oil into the system if the level is going down and gives you piece of mind that oil is being added automatically.

If you are that concerned about exactly how much, then follow the service manual procedure and measure it