When should one consider changing a Carb'd SWSII to Premix?

[Walkers Edge]

I have a 1998 Yamaha 200hp SWSII, the carb'd engine. It has relatively low hours (estimated 250-350) most of which have been put on my myself in the last 1.5 yrs. Engine has been trouble free, meticulously serviced and well cared for.

With these oil injected carb'd engines I know one of the weak points is the oil injection system so I am trying to get a feel for when (or why) one should consider scrapping the oil tank, making the adjustments and going with premix. I know there are drawbacks such as reduced fuel "shelf life" once premixed but with my usage it shouldnt be an issue, any others I am overlooking?

Obiously this was more common on the old OMC vro engines but I have come across some yamaha guys that did it as well. What problems typically prompt this action? All input is greatly appreciated.

 

[Parthery]

Run it forever with the oil injection. The Yamaha system differs from the old OMC systems in that there is a tank under the cowling which feeds the motor. The remote tank in the boat feeds the tank under the cowling. In the unlikely event of a failure, you can always remove the cowling, fill the tank on the engine with oil, and continue on your way.

The only maintenance item that I would be concerned with is cleaning/or replacing the filter screen on the remote tank pickup. They do get cruddy over a period of time.

The old OMC systems used a remote tank only which fed oil to the engine. If the oil didn't get there, a powerhead failure was likely.

 

[Grog]

Never.

The biggest problem would be contamination in the oil. Replace the filter on the main tank and check the level controls on the engine tank and you're set.

 

[Walkers Edge]

Thanks for the input, I like what i'm hearng. If it aint broke dont mess with it.

 

[BobP]

The OMC VRO pump is very reliable and less complicated than oil injection sys on Yamaha.

If you premix, you will burn more oil, that's the only down side.
Up side is motor will never fail from automatic oil system / alarm warning failure - lack of lube .

That's off course, if you never forget to premix.

Since it's injection now, it takes an action on your part to change, none to stay as is. That's why you are likely going to stay as is.
If you needed a new VRO pump or oil injector pump, oil tank, etc,. why bother to spend more money? Likely would go premix at that time.

 

[ahill]

After 1997 the OMC's were programmed differently and ran like crap at low rpm with mix.

 

[JUST-IN-TIME]

the oil injection is the best out there

as long as you maintain it

that is every year drain the on motor tank and then bleed the lines

 

[BobP]

Now how many drain tanks and purge lines, nor even know how to, nevertheless even once? Forget annually.

 

[JUST-IN-TIME]

Now how many drain tanks and purge lines, nor even know how to, nevertheless even once? Forget annually.

thats the price you pay when the motor breaks down

 

[NOTHING ELSE MATTERS]

JIT, is it easy for the average DIYer to do this?(drain the lines and and tank). Can you give me/us some pointers or if is easy for you; how is it done? Thanks.

 

[JUST-IN-TIME]

BOB P

just did a right up on this

you can do it e-z

 

[NOTHING ELSE MATTERS]

BOB P

just did a right up on this

you can do it e-z

Where?

 

[JUST-IN-TIME]

http://www.greatgrady.com/forum/viewtopic.php?t=12219

 

[NOTHING ELSE MATTERS]

http://www.greatgrady.com/forum/viewtopic.php?t=12219

Thanks.

 

[BobP]

That will be the day most will do it annually. I hope they do.

I wrote it for the purpose of functionally testing the oil indications and alarms and other elements like pumps, as close to real life situation as possible. Which isn't in the service manual nor any other place I read.
Otherwise you wait for the very rare occassion it is called on to work, and it's by fingers crossed it may or may not work.

Kiss of death for motor powerhead if not.

But if there is water in bottom of main tank, it will pump thru entire system into block- no filters will stop it.

So make sure bottom of main tank is cleaned out, not pumped out.

Tank needs to be removed from position and turned upside down over a 5 gallon bucket. then inspect bottom for sludge and if so clean out sludge.
Spray T9 or the like on tank oil pump motor assembly.

The little inline oil filter can be changed at that time since it's readily accessible. Andy SIM sells the filters. On my HPDI there is the same oil filter used again under cowl.

You'd be surprised how much water and the sludge form from it, can be found in tank, due to condensate particularly in those long remote fill hoses and perhaps some leakage in remote fill fitting. The system is vented to the atmosphere (in bilge) via small hole in remote fill neck just below underside of mount. Plenty of humidity in my stern bilge spaces where that little hole vents and sucks in air, place is always soaked back there in season.

That's why I got rid of remote fills, have to use long funnel now and lean into the service door, but want these HPDIs to be around a long time, a very long time. Water is not a lubricant !

 

[Grog]

The remote fills scared me. It's just too easy for water to get in through there and toast an engine. Sure filling the tanks is harder but it's worth it to me.

 

[BobP]

There are three areas of concern with remote fills as part of a LUBRICATION SYSTEM. Based on been there/done that.
You 4 strokers don't have such exposure, for the better.

1. Leaks at O ring on port, doesn't have to be bad o ring, if the area has been recently washed down or rained on, water will sit in the gap and run down when screwing it out. Not to mention loose caps, dirt in O ring groove, etc.

2. Adapter fitting on top of tank to accept hose. Another place water can drop from access door and the like and get into tank (directly or following hose down), I found the flat gasket design on Yamaha adapter dangerous since it's not trapped in a groove. The gasket in mine slipped off neck rim and partially fell in tank - meaning no water tight seal at fittiing as should be. The orginal tank cap has trapped flat gasket design, can't slip out.

3. Entire lenght of 1.5 inch remote fill hose is a perfect condensate generator since it's always empty and plenty of volume, and air that vents tank is bilge quality in terms of moisture (OMC remote fills have vented cap to atmosphere). When I lifted off my hose from tank, water dripped down. WTF? I looked up hose from bottom and entire inner hose was coated with beaded water. O ring seal was perfert. Need I say more.

To me, water in oil is worse for direct injection than carbuerator. Fatal for direct injection. The bottom of the Yamaha on-motor oil tank feeds by gravity into the top of the oil pump below it, same place water collects in oil, on bottom.

I bought a long neck smooth bore funnel and spend a few minutes cleaning out funnel when done. Funnel was about 3 bucks. Put original caps back on tanks. Reused 1.5 inch hose and hose clamps for new scuppers and deck drain job last season. Better off keeping tanks more fill than empty during season, to lessen empty air volume in tank where condesating occurs.

Good luck.

 

[enfish]

Just a thought on a modification that I've seen done and will probably do myself soon. I've seen a few boats that have eliminated the fill hose into the remote tank by simply removing it and capping the fill hole in the top of the tank. To add oil, just remove the cap, insert a funnel and pour away. I've never liked the fill system in our 208 with the oil fill cap inside the splash well. It would be much easier to fill the tank by removing the transom seat cover plate and unscrewing the cap directly on top of the tank.