225 Yamaha Smoking at Startup

[makomeone]

This is a 1995 that once warmed up, all is fine for the rest of the day. I'm using good quality 87 octane and hand mixing (oil pump disconected) 50/1 Yamaha oil. The smoke gets so thick its a spectacle at the ramp.. What could be wrong.. :'

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

your oil ratio is way to high at start up, the precision blend would be about 130/1 at start up/idle.
but check your plug caps,fuel pumps and if its a 2.6L motor the recirc check valves. but its mostly common on prewmix motors as most customers cannot accurately mix at 50/1.
when the motor sits the gasoline evaporates leaving the oil behind, next start up it burns this as well as the over oil rich mix coming in at idle speeds due to the 50/1 ratio.

 

[makomeone]

Re: 225 Yamaha Smoking at Startup

Dont know what to do.. If it's premixed at 50/1 how can the startup blend be anything less than rich when considering the left over oil in the carbs from fuel evaporation. Should I mix at higher than 50 to 1?
You suggest I take it to the mechanic since really I'm the only boat I see with such a smoke problem. Many smoke, but not as much as mine????

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

your motor at low speed was designed to run somewhere around 130-150 to 1 oil to fuel with the ratio decreasing to 50-1 oil to fuel as the speed went over about 3500 or so.
thats why it was called precison blend, it worked very very well and only gave problems if not maintained or it was monkeyed with by a shade tree.
no where in my post have I suggested taking it to a mechanic.
but not knowing what model it is its hard to say much more.
that motor was made in a 2.6 and a 3.1 Liter displacement in 1995 and about all the two shared was paint code. how much fuel are you trying to mix and how do you mix it ?

 

[makomeone]

Re: 225 Yamaha Smoking at Startup

Taking it to the mechanic came out like a statement when I should have added a "?" as in: You suggest?
Sorry...
I might be very guilty of not mixing proper since I JUST bought myself a meassuring container. The way I was doing it is if I put 75 Gls of fuel I'd add a whole gallon plus a half of one. It was an eye thing.. Easy for the 75 gals but not so for 37 gals or any such odd number. I never really thought it had to be so precise..

Mine is the 3.1 litter

Something which might be of interest: In trying to take care of it, since it is over 10 yrs old, I try not to go over 3200-3500 rpms.. That gives me a nice cruising speed of about 30 MPH + which is plenty fast for a 50 yr old driving a 23 yr old boat with a 11 yr old motor...

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

ok, your mixing procedue is all hosed. If you must premix you MUST mix about 1/2 gallon of oil to about 5 gallons of fuel for every 25 gallons of gas, by dumping the fuel in the tank then the oil mixing becomes unknown.
so ya have to kind of have an idea of how much gas your going to add each and every time.
why is the incredibly reliable oil injection removed anyway ?
if all you ever turn is 3500 your damaging the motor and how will you ever know if a carb is clogging ?
what is the max at WOT ?
not saying to run it at max all the time, but to keep the plugs and rings clear that motor likes to run a bit at 5000 or so. it needs to be able to hit 5500 or so.
check your low pressure pumps,especially if idle quality is suffering a bit.
mostly you have more oil at low speed than the motor was designed for, therefore its gonna smoke like a train.
especially when cold and the primestart is adding extra fuel,premixed oil rich by you, to the cylinders during warmup.
the 3.1L motors do not use recirc check valves so eliminate that.
however the 3.1 motors eat fuel pumps, I reccomend replacement as routine maint every 3rd season.
but I have to ask again,why is the oil injection disabled ?

 

[makomeone]

Re: 225 Yamaha Smoking at Startup

My mechanic suggested removing the oil injection because he said it could become faulty in the future and cause problems. He said it was alot safer to premix..

WOT is about 5400... The only time I ever did it was to check the prop for max speed which was about 45

When all is added up, I think the best thing would be to install the oil injection again.. You dont think there is any thruth in removing the oil injection then. Are they that reliable over time? Can it be re-installed again. Is there any permanet damage to the system by removing it

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

depends on who removed it and how it was stored, best advice I can give you is find a trained Yamaha technician. look on the website and you may find a dealer with a master tech in your area. talk to that tech about how many oil injection failues they have seen on a yamaha. the occasional failure,although rare, is the pump shaft seals leak and cause it to over oil.
but your current mechanic sounds a bit shadetree-ish.

 

[makomeone]

Re: 225 Yamaha Smoking at Startup

He is a certified Evinrude man that means well enough but might be a bit old fashioned and not as inclined to newer tech ways.. Before tha Yamaha I had the original 83 200 hp Evinrude on there. This mechanic repowered with the Yamaha at the begining of the year, but since then for different reasons Ive realized that he doent like or isnt fully trained on Yamys.. Just down the road from him is a Yamaha shop that I've visited and have gotten some good vibes from just from seeing the type of boats they work on and their approach.. which like yours is "these a good motors, work within the specs and you wont go wrong" I'll go over in the next few days and talk to them.. Thanks for clearing things up for me - again...

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

your 250 is higher tech then any carb motor built by OMC.
it was a very solid dependable beast
however it has stuff that most OMC techs never saw.
the ign timing and certain air/fuel corrections are ECU controled by a crank position sensor and the throttle position sensor.
it has a knock sensor to detect detonation and retard timing and add fuel to aid in preventing piston damage due to detonation.
the 3.1L motors eat fuel pumps. replace them every 3 years as a maint item.
but you will find its difficult to accuratly mix gas and oil in a large tank.
I just replaced the OMS pumps on a pair of 95 225 evinrudes cause the guys previous mech had removed the origanals.
the customer found that premixing a 220 gallon tank was to much hassle.
on the OMC/BRP stuff I reccomend replacing the OMS/VRO pump at 6 year intravels and testing the alarm system bi-annually.
all oil injected motors that have inline and/or in tank filters need annual oil filter maint.
this stuff aint hard but even supposed certified techs cant or wont do the maint correctly.
however it does keep me in a comfortable income bracket.

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

sorry it should read 225 insteaad of 250, however both 3.1 225 and 250 were basically identical. both used a 76* block and the V76 ign system.

 

[makomeone]

Re: 225 Yamaha Smoking at Startup

You are right about mixing, Its not easy and could be deadly to these motors. I visited the Yamaha shop and the guy said that so much damage could be cause that he has actually had to replace power heads. He also said the pump itself was about 200.00 and labor about 1 hr or so.. Now I just hope my old mechanic still has the oil container he took off, somewhere in his shop and didnt sell it to someone else...

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

look on the dealers school certificate sheet for a gold sticker indicating the tech has attended the yamaha fuel systems course.
depending on what was removed you may have to buy more than a pump.
the fuel systems couse spends a lot of time with precision blend, however its the area most failed in all the couses including the master tech course. its a very simple reliable system that kicks a lot of technician butt for some reason.

 

[bernieb]

Re: 225 Yamaha Smoking at Startup

Angel B there's a oil pump on ebay you can check into.......item # 220022070540 not sure if it will work or not

 

[rodbolt]

Re: 225 Yamaha Smoking at Startup

I dont trust any ebay sheet. all I ever saw that customers bring me are junk.
to many techs blame oil injection for failures out of ignorance.
if the cooling system is working fine and only one piston lets go and no crank damage is evident they will still blame the oil injection.
other than the first 2-3 years of the OMC VRO actual oil injection failures from all makes was rare.
merc has some issues with the nylon drive gear motors but all failures of that could be tracked back to improper storage or overheat,
folks this aint rocket science,fix it once fix it right,use factory parts in accordance with the manual and service bullitens and it goes and goes.
in about 30 years of doing this I have only actually seen 2 motors wear out.
both were over 15 years old and were daily use commercial rigs.
the rest died due to neglect.

 

[makomeone]

Re: 225 Yamaha Smoking at Startup

I have a simple approach to boats. "keep it simple and take very good care of them" They will cost money to keep up. But, if you get it in the hands of good mechanics and spend what you have to and take care of it, then you should do well out there. I thought about a used pump, but decided that it's not like one is free and the other $500.00. Its more like a 100 dllrs in probable savings and thats not worth it. The shop has an opening in about 3 weeks time. Hopefully, Ill have a chance to tkae her out once or twice before I take it in.
Im going to ask them to check everything, including the fuel pump that you say this motor eats up.. If you have any other recomendations, Id love to hear them..