Yamaha OX66 225s- Tell me everything
 

Question for all the mechanics out there...
Tell me what I need to know about 2000 Yamaha OX66 225s.

Ummm... Their made by Yamaha. They are 225 horsepower and they are Model OX66's... :hide:


Sorry Skunk... I just couldn't help myself.... :you:

Only thing i know is they like yamalube and this magic stuff called ring free.

I don't have much experience with them myself. I know it's an old school 2 stroke design engine with basic fuel injection, but I believe the ox66's used an oxygen sensor mounted in the powerhead in the top of the exhaust port to provide air/fuel data to the ecm to help eek some milage out of them. I know I've read the O2 sensors were problematic in them and required frequent cleaning. Otherwise they're supposed to be some of the best engines Yamaha turned out.

good solid engines, basic EFI. They like gas though. If you want to get ahead of the curve and get it all ready for next season. Plan on doing some off season maintenance to them. O2 sensors are easy to clean, remove from housing, heat till cherry red with a MAp torch, let cool off and reinstall. Make sure to clean the passage into the cylinder and the little barbell thing with Merc power tune or parts cleaner of your choice. Yamaha sells the gaskets needed as a kit. Replace thermostats, be care full, those little bolts break off easy. Replace water pump impeller, use Yamaha factory kits only. If it doesn't have a water separating filter for each engine, install one(new fuel hose doesn't hurt). If you're up for it, take the VST(fuel tank assembly on the engine) apart, clean it out, replace the screen on the fuel pump. While its off, check or replace the mechanical fuel pumps. Tighten the bolts holding the pumps together, there are three of them. If you think you need diaphragms, check the price on the whole assembly, they're not much more than the rebuild kits. Run good fuel, good oil and ring free and you should have good service out of them. Items of note, they only run on four cylinders at idle, so don't get freaked out of it seems like they aren't hitting on all 6, they aren't. Trim motors and fuel pumps are very expensive from Yamaha, the aftermarket is supplying good alternatives for them now.

thanks!

Friends with em ' tell they burn a LOT of fuel and a LOT of oil.

Outdated technology and performance.

Outdated technology I'll give you, outdated performance is a big negative IMO. I know DFI's run good, but it's tough to beat the performance AND lighter weight of the old school 2 strokes. And the 225 ox-66's were true beasts utilizing the larger displacement block of the 250's. So yes, they use 5-10% more fuel and probably 25% more oil than a DFI in an average outing, but they do have there benefits to many boaters still.

OK so we've run them a bit now.

had to replace a thermostat housing (cracked at bolt and dribbled very slightly)

Stbd engine tops out at 4600. Port over 5000. Prop on stbd had work done, maybe problem???

Rpms/throttles match up until 4000, then stbd has to be pushed farther than port.

Both at 4200 she hums along at 33 mph/33gph and sounds great. Had it up to 38mph.

best fuel burn at 25 mph/22gph.....ouch!!!! (has yammie fuel flow meter)

tilt position sensor on stbd not working...haven't investigated yet.

Stbd fuel pumps look brand new.

HATE the blue smoke. Haven't had a 2 stroke since 2003. You really get used to breathing....

LOVE that the boat was easily worth $22k without any motors so I can't complain about running motors.

Hope to run these next year and scrape and save and beg and borrow to get new 200 yammie or zuki I4 four strokes in the future. That'll last me right to retirement....

based on a twin F150 repower I just completed, you should be able to buy over 10000 gallons of marina fuel and oil for the price to repower that boat

and by the way, those engines are highly sought after in offshore countries as they are not as fuel finiky as four strokes

I have the ox66 250, this is only my first year with it. And since Spare help me get this thing running rite its been a great motor with gobs of power . And everyone I speak with that has one is very pleased with it.. that's all I can tell ya.

Yep I know its a big nut...and I'm a cheap b@[email protected] thought is to run a full year and really decide if going BIG was a good move. If I decide this is the boat for the next 15 years then...

Factors for repowering-
Really can't stand the smoke
200 four strokes would probably double the mpg...canyon trip 100 gallons vs 200 gallons...over 15 years that is a big number to help offset repower$.
These are 17 years old so they will require constant repairs, some nickel and dime(just ordered an oil tank pump) and some not so cheap..
That means more down time and this is a big boat/no trailer...$$ and hassle to pull to work on.
Likely that at some point I will be forced to repower anyways so I might as well do it early.
These running motors are worth something to sell right now to lessen the hurt of repower.

Factors against-
from a total $ perspective its only worth it if I keep the boat for 15 years or so.
Have to tell wife I'm spending $35K on motors:nut:

And, being able to sell running 2 strokes better than trying to get rid of non running 2 strokes

You will not double your milage unless you troll ALOT, and I do mean ALOT! The fuel economy diffetence for long runs is no where near as much as most think it is. At idle to low load situations, yes, you will see a big jump, but at cruise to wot the realistic improvement should be in the 10-25% range of improvement. I currently havea 4 stroke because that is what was on the boat I found I liked, but I would have just as easily have gotten one with 2 strokes. If you're after mpg, then a direct injected 2 stroke will most likely beat out even the 4 strokes in most areas.

As to hating the smoke, have you tried a better quality oil like pennsoil synthetic blend? Yamalube is a good oil, but I had the least amount of smoke with the pennsoil. Also make sure the oil injection pumps are adjusted correctly. Even 1 turn out of adjustment can make the difference between smoke or no smoke. I had a 25HP Suzuki YEARS back that fought me fouling plugs, ended up being the pump was 2 turns out of adjustment. It actually fell within theallowable limit, but adjusting it dead on cleared up all the smoke and no more plug fouling.

So checking things out, running different battery switch positions its clear that the port engine is not charging and wont run without a battery. Gut reaction is Rectifier/regulator. Anyone know if there is a fuse in that circuit?

its not supposed to run without a battery,

two big fuses and a spare under the back cover on the port side of the engine, Yamaha engines have two charging systems, nice to use if you have a separated house battery.

https://www.google.com/search?q=ox66...d1-Sduze4rOrM:








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so I replaced the rectifier (without really troubleshooting cause I am a dummass). rectifier didn't fix it. So measured the stator (green wires) 0v AC....open resistance between all 3 green wires...looks like stator....

anyone know if you can pull that flywheel with a steering wheel puller?...don't have the yamaha tools for that.

hoping I find a fixable broken wire cuz its $600 new and $150 used and used is a crap shoot.

36mm socket wrench- $20 AutoZone
Bolt-type wheel puller- $14 Harbor Freight
18" by 1/2" breaker bar wrench - $10 Harbor freight

Pulled flywheel and yes ..stator has broken wires.
Debated used on ebay $140 or new at Boats.net $593...went with new.
Waiting for part...
https://i.imgur.com/NuQqLev.jpg

I don't want to seem like I am doubting you, just asking for a little more info...

We figured since it has an emergency pull start rope, that it should run without a battery...so we tried it and it shut off...
Then we turned off the battery to the running Stbd engine and it kept running...

after that we read the warning on the switches "Don't shut off while engines running"

did I mention I don't have battery switches on the V20 and was just winging it. Had been running them on BOTH which caused the uncharged battery to drain the charged ones when I left the switch on Both overnight....new boats!!!

I think the PO had some inkling as to a charging problem because all 3 batteries were brand new and he had both Stbd and Port Aux charging wires to the port battery.

So new stator and regulator gives us 14.5 volts DC unloaded, which is nice.

Did that fix your uneven power problem?

no, actually the charging problem was on the port motor that gets above 5000.

We did loosen up the controls...snapped off 2 of the 4 allen screws holding the binnacle cover. Lubed the linkage at the motors. Smoother and easier to push and shift.

Suppose we could run with cover off and try to work throttle from there, if we get to 5k then linkage needs adjusting?

Bought a Seloc manual on eBay $25...great if work on every motor from 2 hp to 250 and you already know what you are doing. Should have bought a Yamaha manual for SX225/LX225...$90 from Yamaha.:nut:

I think the prop is definitely a contributing factor, I can see a difference..

Funny thing, if I read fuel meters separately, the stbd motor actually burns a hair less fuel when they are both running at 4200

if you can "see" a difference in props, then there is definitely an issue. I had props that look perfect were way off. What props are on the boat?

haven't had the chance to get a good hands-on look at the props. Guess thats my next project...after fishing tomorrow morning...

Assuming they are marked the same size....PO said he had the stbd one repaired.

Edges look different, not cupped like the port one.
I'll get the size off both and maybe get another to match the port side...throw money at it...see what sticks....:nut:

By the way, we found some poor connections and green copper on some cables from the house battery and now that side is also measuring 14V when we are running. So we are making progress. Installed 4 more new rod holders also...

When having a prop rebuilt, I always reccomend doing them in pairs. Many shops use universal dies to shape the blades which can be good or bad. Many times a certain size of prop can comein 20 different blade types, or more. You really need to have a prop rebuilt on a die made for just that specific prop, but that can mean a prop shop must buy 20 different dies in every pitch size. This can add up to thousands of dies, so they use universal dies to use to rebuild, shape, and contour the blade. It only takes the slightest of differences in prop design to completely change how a prop works or even how the boat rides. Having both props done at the same time means they can at least make them both similiar. You may even benefit from a prop swap. For a big boat like that with big v-6 2 strokes, it would do well with a set of mirage plus large diameter props. It would help out with prop hookup down low, and they lift the stern pretty well to help plant the bow down which helps in thechop to keep the sharp part of the v bow doing it's job instead of running bow high and slamming the flatter hull bottom.

What Ferm said

Here's what I mean about looking different. You can see the starboard prop's edge has been reworked. Have't got a lot of enthusiasm for removing props while in water but thats the only way to get numbers off them....

https://i.imgur.com/fU4LdUch.jpg

look near the back of the prop hub, right where it flares out, if they are Yamaha Props(looks like it), it will have something like 17M embossed in the prop. Do what Ferm said, pull them both and carry them to a reputable prop shop and have them checked

I can tell from the pics that the starboard prop has a good bit more cup to it. The cupping is one of the 1st parts to wear off, and can make or break how some props perform. Those aren't quite a semi-cleaver blade as they're rounded instead of squared, but I would say they look like Yamaha props as they use blades with a semi cleaver design alot as they allow the boat to plane easier and give better low end performance. They also lift the stern really well which is the main reason they perform so well down low. That blade design NEEDS a good cup to the blade tip or else they blow out.

Yea but they only have to run 2 miles off the beach to be in the pelagics!! Lol!!!

so I've been calculating it out...ignoring maintenance of 17 yr old motors...
:head::head::head:
Low price for gas at dock - $3 gl
Low price for 2 stroke oil - $.40 per gl of gas ($20gl oil/50gl gas)...Pennzoil $20gl...Yamalube is $50gl
---- low price of fuel $3.40 gl

Canyon trip burned 220 gl for 3 hrs out/3 back /4 hrs running around and trolling 220/ 10 = 22 gph

Expect to run 100 hrs /season = 2200 x $3.40=$7480

Lets say 4 strokes knock it down to 15gph x 100= 1500gl...x $3.40=$5100

Lets round it to $2400/year fuel savings

Pair of zuki 200s- $34,000/10 years...$3400/year- $2400/year fuel savings= $1000/year for new 4 strokes
:head::head::head:

If gas higher=more savings
if run more due to more canyon trips= more savings
If keep boat more than 10 years= more savings

:head:spending money SAVES money!:head: I wonder if my wife will buy that:head:

mawshj
 

2 strokes have a very small number of moving parts vs 4 strokes and are a lot more forgiving of gas contamination than4 strokes

i've got 420 hours on my 4S and i figure it's save me 3 gallons an hour, so thats 1260 gallons. at $3 per, thats $3780. im trying to get to 1000 hours so it will pay for itself.

when presenting to wife, feel free to reference this to her

good luck

I have ~1200 hrs on my DF140

Don't forget the added maintence costs of oil changes, filters, zincs, ring free, and so on when figuring your actual numbers. The cost of 2 stroke oil is pretty much offset by the cost of oil changes. I see where you're going with this presenting it to your wife, but be honest with yourself. And if your props are as bad off as you're saying they are, you can probably get a new set of props and reduce your current fuel consumption. The only real advantage I see is newer power and the hope of increased reliability, and if you do sell it, there will be a large increase in resale value. So they each have there pros and cons. Personnally I would get what you have fixxed, setup, working 100%, and run it like it is for a year or at least 3 months to see if it's the boat for you and if you will still be using it as much as you hope to after the new wears off before I would repower. I know that the idea of repowering is very tempting right now as many dealers want to move inventory in the off season and are willing to deal. But I would spend some time with it before I went sinki,g more money into it than you bought it for for a pair of new engines.

:head::head:
8(?) qts x 2 motors = 4 gallons of 10W40=$20x4=
$80 per year + (2 Suzuki oil filters x $19=$38)=
$118.

$20/gl 2 stroke oil x 2200 gl gas per year/50 (50:1 ratio)= 44 gl of oil x $20=
$880...for 2 stroke oil per season...that can't be right???

Ring Free need for 2 stroke - forgot about that...
WOW :cen: $50/qt for every 320 Gallons of gas...2200 gl(expected gas per year)/320 about 7 quarts x $50= $350/year

$118 vs $1230

I like the new engine smell myself, but I'm with Ferm, get your props right and run the heck out of those ox66s for a couple of years. You can always repower. To me it doesnt make sense to remove clean good running engines.

But then what the heck, its your boat, if new makes you happy, its only dirty green paper and you fish enough to get return on the investment. Even if just on the personal satysfaction side of things.

Reconsider ?

Evinrude offering 10 year non declining warranty on their G2 Etecs.

Power and performance of 2 strokes.........plus the rather amazing features of these G2's
and fuel / oil economy..

I know I want one hanging off the back of my boat. If only I could afford it.

its all about time. 17 year old motors there is a good chance of needing to do major repair or replace at least one in next few years. If I'm keeping long term, I might as well have new motors and spread the cost out over time than run old motors for years and be forced to buy later anyways...
That said, unless some lottery numbers come in, I'm running it next year with these and making a decision about the boat. That will inform my decision about the motors.