Premix re-mixing question

[Ozzie Seadoo]

Hey,

I hope this doesn't make me look stupid. I am rebuilding a friends 720 engine (have already rebuilt my own), but he wants to convert his to premix. I am fairly against premix, only because it is in-convenient.

My question is how long does premix last before the oil and fuel seperate and have to be remixed. An example....say he rode his ski, left it overnight and rode it again the next day....would the fuel and oil seperate in that time. I'm all for premix on his ski-i just want to be sure what the correct methods are....have already read previous posts about correct mixing techniques, etc.

If i do premix it and leave the large oil bath lines going to the bottom of the crankcase, do i ever need to change the oil in the oil tank? (which would only supply the crankcase oil bath). I thought maybe change it each season as it may get dirty??

Thanks for any help.

[swiftman]

Re: Premix re-mixing question

It wouldnt happen overnight, Im not 100% sure the max safe limit to leave mixed fuel is... I dont leave mine for over 3 weeks unless I at least add 50% of fresh gas to it.

[ncdoo]

Re: Premix re-mixing question

Dont, worry about it, I leave mine in over the winter (6 months) with no problem.

[parrothd]

Re: Premix re-mixing question

It'll be fine, just add some stabile to the tank to prevent the fuel from going bad if your planning on letting it sit for months. Even if the fuel/oil did seperate(which I highly doubt) when you started or moved the ski it would re-mix.

You don't need to spend 5 minutes shaking the stuff, it mixes very easily. Add the oil to the tank/can and watch the color, you'll see what I'm taking about, or just add the oil first, then add the gas. Leave the oil bath installed, no need to change the oil..

[Bill O'Neal2]

Re: Premix re-mixing question

The sump oil doesn't get too dirty, as there is no carbon from cumbustion anywhere near it. Over time, the oil level will slightly drop, as some always seeps into the crankcases.

[Ozzie Seadoo]

Re: Premix re-mixing question

Ok, thanks guys that helps me a lot. Can i ask (if anyone knows)....can i rely on the petrol station meters being correct...IE: If i want to do 40:1 for my seadoo, i'd put in 1 litre of oil and 40 litres of petrol (we have litres in Australia), then will the petrol bowser be accurate (ie: Hoping it won't say 40 litres when 43 litres is in there).

Also, after breaking in at 32:1, will it be better for my engine if i run a slightly higher oil mix (ie: 38:1 instead of the nominal 40:1 for a seadoo)




Thanks.

[dsolie]

Re: Premix re-mixing question

You will need a different ratio: kind of...

In the US it's 40:1 = (16oz of oil / 5 gallons of gas) 3.2oz of oil per gallon of gas

In liters.... You will need 1/2 liter of oil for every 19 liters of gas.... I think that's right lol...

[Ozzie Seadoo]

Re: Premix re-mixing question

He he....yeah it gets confusing hey dsolie!

I'm pretty sure it should be 20 litres of gas to 0.5 litres of oil, not 19 litres....but hey. I thought the whole 40:1 ratio thing meant put in 40x as much gas as oil??? No?

[parrothd]

Re: Premix re-mixing question

Geezzz.....just spend the $200 and buy a new oil pump..:emoticonn

[kiwiguy40]

Re: Premix re-mixing question

Metric formula is: 40:1 1000 divided by 40 = 25 ml per litre
If you have 20 litres of fuel, add 500 ml of oil

[Ozzie Seadoo]

Re: Premix re-mixing question

Parrothd,

$200 US = $400 in Australia once you add shipping and tax. Also i can't find someone even on this site who sells oil pumps. They are not that common/hard to come by in Oz.

[kiwiguy40]

Re: Premix re-mixing question

Hi ozzie,

The JET SKI WAREHOUSE in Brisbane rd Labrador, Gold Coast has second hand and rebuilt pumps in stock. second hand with a 30 day warranty are around $150.00 + freight.

[Ozzie Seadoo]

Re: Premix re-mixing question

Thanks kiwiguy40, i'll give them a call....That gives me a place to start so tahnks for that.....i'll try to get a new one......why do they do rebuilt pumps?? I though most dealers would stay away from something like that due to the possibility of breaking??

[parrothd]

Re: Premix re-mixing question

I bought a new pump off ebay for $150....It's well worth it, after you spill the oil on your hands/ski a few times you'll switch back. The worst is getting oil/fuel on the gas can handle, it gets everywhere.. :)