Cruisers Forum
 


Join CruisersForum Today

Reply
 
Thread Tools Search this Thread Rate Thread Display Modes
Old 26-04-2020, 02:15   #1
UFO
Registered User

Join Date: Oct 2017
Location: Perth
Boat: Lagoon 440
Posts: 495
2 Stroke Oil Mix

I have a 2 Stroke Yamaha 15HP Enduro (Just found out its a 2016 model).


Just brought it home to do a Carby service as its running a little rough and pulled the plugs to find them oily (see pics).


Previous owner told me to use a 50:1 Mix - But Manual says 100:1 But many people on this forum espouse 50:1 - As its a 2016 model should I be going 100:1?



Is there anything else that could be causing the plugs to oil up or should I simply go to 100:1?
Attached Thumbnails
Click image for larger version

Name:	Plug 1.jpg
Views:	70
Size:	39.5 KB
ID:	213731   Click image for larger version

Name:	Plug 2.jpg
Views:	64
Size:	56.7 KB
ID:	213732  

__________________

__________________
https://www.thecruisingcat.com
UFO is offline   Reply With Quote
Old 26-04-2020, 02:56   #2
Registered User

Join Date: Jan 2018
Posts: 2,449
Re: 2 Stroke Oil Mix

Why don’t you give 75 to 1 shot for a little while?
__________________

Chotu is offline   Reply With Quote
Old 26-04-2020, 04:22   #3
Moderator
 
a64pilot's Avatar

Cruisers Forum Supporter

Join Date: Oct 2013
Location: Jacksonville/ out cruising
Boat: Island Packet 38
Posts: 30,569
Re: 2 Stroke Oil Mix

I’d stay at 50 to 1. Is the plug actually fouled or just oily? It doesn’t look fouled.
I’d suspect a rich fuel mixture and that of course will bring in more oil along with the increased fuel, good news is that no two stroke was ever hurt with a rich mix, it could just be you need to do an Italian tune up more frequently.
100 to 1 is done for reduced emissions, it’s not that the motor needs it or will foul plugs etc, it’s that the motor will have reduced emissions if you use half the oil.
It will tolerate it obviously but in my opinion at an increased wear rate.
Back in the day 25 to 1 wasn’t uncommon and 50 to 1 is actually pretty lean.

However having said all of that if your engine spends its life at low RPM and loads, then 100 to 1 will be fine.
The last days of most two strokes they had variable rate injection and at low loads they would inject extremely lean oil mixes, down well less than 100 to 1, but as you ran it harder, the amount of oil would increase drastically.
Pre-mix is of course not variable and sort of a mix it the strongest, that way your covered at WOT.
I haven’t had a two stroke in a coons age, but I believe the Enduro models spec 50 to 1 and it’s only the leisure models that are 100 to 1, and I believe that reflects the intended use model, Enduro’s are expected to be run hard and run often accumulating a lot of hours on commercial boats, Leisure models only on some weekends on pleasure boats.
It’s not that the Leisure models are built better or out of superior metals or superior design.

So in my opinion 50 to 1 is best for the motor, but it significantly increases pollution, 100 to 1 will cause more wear, but burning half the oil reduces pollution. I guess it depends on how environmental you are, but if you are, get a good fuel injected four stroke, I bet it takes 10 of them to pollute as much as one two stroke.
a64pilot is offline   Reply With Quote
Old 26-04-2020, 06:25   #4
Registered User
 
Sailmonkey's Avatar

Join Date: Sep 2009
Location: Houston
Boat: '76 Allied Seawind II, 32'
Posts: 7,899
Re: 2 Stroke Oil Mix

I vote for leave it at 50:1 and run it hard.

We’ve got a little 5hp 2-stroke on a small dinghy that won’t plane with 2 people in it. I run it 50:1, run it hard to make a hole in the water, and have never had a problem with oiling of the plug.
Sailmonkey is offline   Reply With Quote
Old 26-04-2020, 06:49   #5
Registered User

Join Date: Nov 2014
Posts: 1,165
Re: 2 Stroke Oil Mix

Well, you could run the manufacturer’s recommended oil, the recommended oil mixture ratio, and the recommended spark plug heat range, but then, what does the manufacturer know?

Probably nowhere near as much as the prior owner and everyone else.....
DougR is offline   Reply With Quote
Old 26-04-2020, 09:01   #6
Registered User
 
anacapaisland42's Avatar

Join Date: Aug 2009
Location: Ontario, Canada
Boat: Challenger 32 1974
Posts: 481
Images: 3
Re: 2 Stroke Oil Mix

I've run my 1984 Yamaha 9.9 2 stroke on AMSOil 50:1 mixture from day 1. The only repair in 36 odd years has been one impeller replacement. It gets new spark plugs, let me see, I guess every 10 years. It has done thousands of miles double duty as the main propulsion on our 32 foot sailboat plus the main propulsion on our 16 foot heavy metal fishing boat plus as the main propulsion on our 2 RIBBY's. It spent one winter frozen in when I broke my leg and couldn't get it out of the water.
So....for my $ 50:1 AMSOIL ......with whom I have no connection other than being a happy customer.
Bill




Previous owner told me to use a 50:1 Mix - But Manual says 100:1 But many people on this forum espouse 50:1 - As its a 2016 model should I be going 100:1?
anacapaisland42 is offline   Reply With Quote
Old 26-04-2020, 09:16   #7
Registered User

Join Date: Mar 2020
Location: Cambridge Md, on the eastern shore of the chesapeake Bay
Boat: 198 carolina skiff
Posts: 11
Images: 1
Re: 2 Stroke Oil Mix

I am in the 50:1 crowd , engine lube is not where you skimp !
khoff is offline   Reply With Quote
Old 26-04-2020, 09:22   #8
Registered User

Join Date: Apr 2012
Location: Cheshire, CT
Boat: Morgan OI Ketch 36'
Posts: 53
Send a message via Skype™ to Mazu
Re: 2 Stroke Oil Mix

I have a 1986 15 Enduro and run 50:1. No issues at all with the engine. I had to replace the steel tilt bar with the aluminum upgrade as it froze but you probably already have this upgrade. I bought my boat in Puerto Rico where I lived back in 2010. The Enduro 15 is a Caribbean motor. That was the target market and there are hundreds of these engines down there. Most of the engine failures I know of were from overheating due to a worn impeller. I change the impeller, zinc and lower end lube every year and I expect the motor will outlive me...
I did have a little low speed fouling of the plugs and would have to open up the throttle now and again but sometimes had to pull the plugs and clean them. When having the tilt bar replaced I brought this up to the dealer who suggested the next hottest plug. I switched plugs and never had a hesitation or stuttering problem again.
Mazu is offline   Reply With Quote
Old 26-04-2020, 09:31   #9
Moderator
 
Pete7's Avatar

Cruisers Forum Supporter

Join Date: Aug 2009
Location: Solent, England
Boat: Moody 31
Posts: 13,652
Images: 14
Re: 2 Stroke Oil Mix

Quote:
Originally Posted by UFO View Post
Just brought it home to do a Carby service as its running a little rough and pulled the plugs to find them oily (see pics).
Just before the engine was shut down for the last time before the plugs came out, was it being run slowly or idling for any length of time which might have caused it to oil up?

Pete
Pete7 is offline   Reply With Quote
Old 26-04-2020, 09:56   #10
Registered User
 
letoile's Avatar

Join Date: Aug 2011
Location: Ontario, Canada
Boat: Beneteau First 235
Posts: 35
Re: 2 Stroke Oil Mix

DougR, has it right with one qualification. The grade of 2cycle oil used is as important as the ratio. The 100/1 oil is engineered to run at that ratio , the same as my Stihl weed eater and Suzuki 2 stroke I use 40/1 oil and mix at that ratio. My Jonsered and Husqvarna chainsaws are 50/1 with Husky 50/1 oil but I run it 40/1 with my standardized Stihl 40/1 oil for simplicity sake. The Suzuki is 30 years old.
Thus you need to ensure the grade of 2cylce oil also. I never liked the sound of 100/1 ratio even with the 100/1 oil. I also mix a little richer and will put up with a little carbon build up and to save wear and tear on the engine. There is a downside of too rich a mix and that is a carbon built up on top of the cylinder that can actually cause premature firing when motors get hot( chainsaw).
letoile is offline   Reply With Quote
Old 26-04-2020, 10:29   #11
Registered User

Join Date: Mar 2020
Location: Quebec
Boat: Tanton,37
Posts: 10
Re: 2 Stroke Oil Mix

You are taking of Yamaha engine the older models were 50 to 1 and the new models are 100 to 1 i don't believe these change were made whit-out intensive test. Excess of oil create carbon build up on piston seal ring.
tangara is offline   Reply With Quote
Old 26-04-2020, 11:37   #12
Registered User
 
Vasco's Avatar

Join Date: Apr 2004
Location: Toronto
Boat: CS36Merlin, "La Belle Aurore"
Posts: 7,499
Re: 2 Stroke Oil Mix

When the old 2 strokes were allowed in Canada Yamaha would call for a 100:1 mix in Canada. Buy the same engine in the Bahamas and it called for a 50:1 mix. I heard that the only reason they went to 100:1 was because of EPA rules. To the OP, are you running the right plugs? I always use NGK BR7HS-10. As to 2 stroke oil I always use TC-W3. And I always run them with 50:1 mix.
__________________
Rick I
Toronto in summer, Bahamas in winter.
https://groups.yahoo.com/group/beneteau393/
Vasco is offline   Reply With Quote
Old 26-04-2020, 12:23   #13
Registered User

Join Date: Dec 2014
Location: Summer Europe Winter Florida
Boat: Dufour Nautitech435/FP Venezia42/Baltec Visiona 40/Catalac 10m used as a river cruiser
Posts: 156
Re: 2 Stroke Oil Mix

I'm also part of the 50:1 community. If you like to use 100:1 you should or even must use the very expensive two stroke oil sold by the manufacturer of the outboard motor. With 50:1 I use a very common and cheap two stroke oil what is normally used for small motor bikes in France. Btw. if available my outboard runs on Ethanol free Gasoline available in the US in Marinas. My impression was that the motor runs smoother.



James
______________________________________


Florida in winter, Europe in summer
onavegador is offline   Reply With Quote
Old 26-04-2020, 12:41   #14
Registered User
 
BlackHeron's Avatar

Join Date: Jan 2016
Location: Summering on the Chesapeake
Boat: Hallberg-Rassy Rasmus 35
Posts: 550
Images: 18
Re: 2 Stroke Oil Mix

That wet plug is from over-rich jetting, not too much lube oil.

100:1 is EPA emissions nonsense gobblygook from sruffed-shirt people who don't care one whit about how much life you ultimately get out of your engine as long as their negotiated air-quality limits stay under the numbers in their ledger books.. If people want to believe that 100:1 is enough for their engine's lubrication needs go right ahead. If it written down on paper it must be true, right? It's your engine to use and abuse as you see fit.

But the problem here is with your carb, not how much oil you are putting into your premix blend.
BlackHeron is offline   Reply With Quote
Old 26-04-2020, 13:04   #15
Registered User
 
Cheechako's Avatar

Join Date: Aug 2006
Location: Skagit City, WA
Posts: 22,505
Re: 2 Stroke Oil Mix

That plug looks rather typical for a 2 stroke really. They never appear dry to me. The good news is "Yeah, just mix it somewhere between 50:1 and 100:1" ! The plug in my Stihl Chainsaw looks that way mixed properly.

The bad news is the main bearings gave out on my old '94 Yam 15 hp after extensive use. So 50:1 may be better. Fortunately I got help replacing those bearings while in Trinidad from a cruiser ex OB mechanic! A few $ in parts and 1.5 hours.
__________________

__________________
"I spent most of my money on Booze, Broads and Boats. The rest I wasted" - Elmore Leonard











Cheechako is offline   Reply With Quote
Reply

Tags
2 stroke, oil

Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes Rate This Thread
Rate This Thread:

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Water in Oil (Milk-Colour Oil Mix) Sergy Engines and Propulsion Systems 16 09-03-2010 09:51
2 stroke vs 4 stroke? Shaft length? Piper'sGirl Engines and Propulsion Systems 6 06-06-2008 14:08
4-Stroke vs. 2-Stroke Outboards The_PIRATE Engines and Propulsion Systems 17 05-10-2007 04:37
2 stroke vs 4 stroke kickers Capct Powered Boats 7 08-05-2007 12:07

Advertise Here


All times are GMT -7. The time now is 00:16.


Google+
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Social Knowledge Networks
Powered by vBulletin® Version 3.8.8 Beta 1
Copyright ©2000 - 2020, vBulletin Solutions, Inc.

ShowCase vBulletin Plugins by Drive Thru Online, Inc.