yamaha 2 stroke outboard oil

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tyce

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i have always used quicksilver oil before but am now using yamahas own oil (my engine is a yam 4hp)
ever since i used it whenever i turn the fuel tap on the carb floods with fuel and the only way to run the engine is to quickly turn the tap on and off.
when the engine has ran for a couple of minutes its then ok.
i assume whats happening is the oil is causing the needle valve to stick due to a gummy residue and it takes the engine a bit to flush petrol thro and remove the sticky oil.
the engine is ran weekly i always run the carb out of fuel after use and the petrol/oil is new.
anyone else encountered this with this oil.
 
Very Interesting

Ah - I had exactly the same with my collection of erm - Seagull(s), I thought it was the antique carburettor.

Now I wonder.... BTW I use quicksilver, mainly because that's the brand most readily available.

As an aside (well not really), I noticed when I went into my local car accessory shop that they were selling three types of two stroke oil, "cooking" semi synthetic and fully synthetic based mix. I got to thinking whether the base oil has much to do with it? Would synthetic oil be gum free?

I KNOW I'm talking about oil for air cooled engines, but there must be a mix for water cooled units.

Can anyone add some flesh to my suppositions??
 
Ah. Except I got exactly the same symptoms on my Yamaha 4HP 4 STROKE.
Fitting a new needle valve seems to have cured my problem at only £28 (gulp) That's the needle assembly, I don't charge labour.
 
Over many years, in big 2 stroke engines and tiddlers, I have used Quicksilver, or mainly OMC oil.

Never had a problem, never had bad smoking, never serviced a carb. My current Johnson 4 needed the head off last winter 'cos of a minor leak. Didn't need a de-coke (16 years old) and I changed the plugs for the first time, but saved the old ones 'cos they were fine, if rather worn.

Never HAD to clean the plugs, though I have doen every year or two, only because I had taken them out to take a look.

Bin the Yamaha oil, buy OMC.
 
I\'m not an engineer but .....

But my Go-Kart many years ago ... a full pukker race job - not yer lawn-mower engine job !! had a sticky needle.

The guy who looked after my engine with me - took it out and polished it ... worked fine for a while then started sticking again. He replaced it with new ... polished old and put in the spares box. His reasoning - that the needle develops a tiny groove / line on it that is literally not detectable by eye - but is enough to stick until enough oily fluid has passed to ease it ...

Seems credible to me !

Me I use any 2T oil I can get where I am ... often its not Marine grade ... as I'm a real scrooge ! My engines are going strong still after many years .... I even use old petrol as well - some used this last May Yarmouth meet was over a year old and it was mixed back then as well !!
 
Re: I\'m not an engineer but .....

[ QUOTE ]
I even use old petrol as well - some used this last May Yarmouth meet was over a year old and it was mixed back then as well

[/ QUOTE ]

And the engine started with only a couple of pulls, if I remember right.
 
Re: I\'m not an engineer but .....

Yep .... open fuel ... leave for a few secs to fill carb ...

Pulled through a couple of times till it coughed on full choke. Choke off - pull - away it went.

Malcb - you also remember that I couldn't remember if 2T was already in the mix ... so added another "guestimated" dollop !! Very scientific !
 
Re: I\'m not an engineer but .....

thanks for info sbc, it does sound plausible to me too.
i think i will try quicksilver oil again and if theres no change will try a new needle
 
Re: I\'m not an engineer but .....

I am using a 4 stroke now .but used small 2 strokes for decades on cheap 2 stroke oil. Have to admit to needing to clean the carb about once in every 5 seasons other than that no problems.I allways run off the fuel in the carb until the engine stops which must help.
 
Re: I\'m not an engineer but .....

I would be inclined to clean the needle with some very fine polish like Brasso or even finer .... polish it to shine ....

Take a pipe cleaner and see if you can similar clean the opposite part .... get them squeeky clean ...

then try fuel through etc.
 
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