Opti rebuild

[bobthebuilder]

That's correct F S it sprays the top of the piston with the fuel... Thing is a rebuild on an Opti takes a couple days at best and I can blow up a 2.5 and if it does not hurt it too bad I can rebuild it in a day and run it again tomorrow. This Opti blew the #6 before as I found evidence when I took it apart that is has been into before and the other cyls. are factory and still in good cond. And this time #6 took out the sleeve and the block underneath the sleeve that was left had a couple small dents under the part of the sleeve that was still in tact.. I bore it to the OS size sleeve and the dents were still there a but very small. Just t be safe I called Advanced Sleeve and talked to Jeff Zaugg and he said just clean it up and give me your cyl size an now he is making a sleeve little bigger than the OS size... this way I only cut the very minimum out of it.. If I had a tig in my shop I would have done some welding before I started then the OS sleeve would have fit. But it is only a little bit more.... I am covering all bases to make sure it does don't blow this cyl again... such as air and fuel injectors sent to Brucato and a new bottom double seal. It was most likely those 2 small dents someone left in it before when they put a STD sleeve back in it without boring the aluminum part of the block... But that's how my friend got a super deal on the rig.

[bobthebuilder]

I am looking for a good deal on a TIG right now. My friend near by here usually does it for me but he was away on vacation in FL... Guess I could have waited for him to get back home.. But sometimes I need one right then..

[Motv18]

You going with carbon reeds and all the goodies.

[bobthebuilder]

I got to ask my customer but I personally advise them.. Best goodie is a 2.5 LOL

[2jz]

Premix on DFI motors is a big no no per mercury service manual.

The ecm plays a very big role in performance. IMO Port timing is the same. Lets compare mercury 250hp line optimax, pro xs, and xs racing all have different rpm limits and fuel mapping via ecm with xs racing out performing all with higher rev limits and a few other little tricks.

Good old #6 cylinder is always a problem it looks like from reading about 3.0l motors. My 03 and 05 powerhead same thing with 03 killing sleeve, rod and crank. So in my little world thinking what makes #6 cylinder different from the other 5 cylinder. The #6 cylinder crankcase pressure is what feeds the 3gal oil bottle to supply powerhead oil bottle. The less oil in 3gal bottle the more #6 cylinder has to keep bottle pressurized. Lol sounds off the wall but for this reason of thinking I always keep my 3gal full. Just my two pennies.

[bobthebuilder]

I would think it is best to keep it full as possible too. One thing I think could be improved on is that system of pressurizing the oil tank.. but if it is pressurized it helps keep the water out of it. BUT , I do not like to rob crank case pressure to bring the oil to the engine tho.
I sure do like my 2.5 260... ! I was very happy with a 225 PM before that and I think it even liked it better on my Gambler. But a 2.5 with oiler removed is so simple an easy to keep maintained. Also it is almost 200 pounds lighter than an OPTI... I thought about an OPTI once but glad I didn't do it.

[powerabout]

The thrust side of the piston is on the exhaust side on one and not on the other?
Left bank makes more power or is that just red herring on a dfi engine?

[Motv18]

Never had problems with water in seven years. Smart tach still reads 15 plus from the pump side not sure where the sensor is though. Interesting how much dfi stuff is still myth.

edit ; oops that's fuel mines not new enough to read the oil pressure

[baja200merk]

premix DFI does nothing but cause more soot/buildup. Excess soot is what gave fichts their bad name I doubt you want your opti to follow in their foot steps.

[Mr. Demeanor]

If your rebuilding it I assume you have a service manual and the instructions for putting it back in break in mode are there.
If not...

[bobthebuilder]

Yes Thanks Mr. Demeanor, I do have a factory service manual but thanks for the pics... Someone else might even need it too. I have done a few maintenance things on one before but this is my first rebuild on one. But I have a lot of past 40 years rebuilding outboards doing machine work and mechanic work also... working on outboards. I cut my teeth on them old 1950's and early 1960's engines and been a life time hobby ever since.. Started doing machine work in a machine shop 43 years ago! But these new engines going green are another story... I like my 2.5 260...

[bobthebuilder]

Brings back many old memories... Once I and a friend modified a 1970 25 hp Johnson doing mods in the porting and reeds and carbs. On an 80 pound aluminum boat with a prop we had specially made 8 1/2 by 13 pitch and the thing would go so fast we could hardly control it .. just almost 20 years old and thought we really had something...

[scc82]

Well this one will not see any WOT for more than 2 hours of running.. The manual says 120 minutes or 2 hours of added oil.. IMO they run them on too little oil anyway. Seems like they would have a special oil with an additive in it to break friction. I have seen something a few years back that was designed for stand by generators which were 4 stroke diesels which start at full rpms when they start up.. They also use an electric oil pump that builds oil pressure about a minute before it cranks up. They call that a pre-lube oil system. But the OPTI's run at about 400:1 @ idling and 60:1 @ WOT is not a lot of oil.. I suppose that's why they only turn them 5600 rpm. The life of an engine is based on keeping the oil going to it. It gets just enough oil to survive..

we rebuild optis a lot, at least one a week in the shop. Everyone that comes apart is completely soaked with oil. They don't have oil problems. You have to remember that there is no fuel running through the motor and past the crank and rods to wash oil off like a carb or efi motor. When we pull a crank out it is actually dripping with oil. I would say they oil better then a conventional motor at least on the crank side. Jmo.
Stan carson.

[timking57]

We have been running our 200xs opti race motor in break in mode. We think sense it has no effect on the performance it can only be a good thing to run double oil. We are on the rev limiter @8500 rpm on every straight away. Anyone have any insight to this.

[Dave S]

Sounds good to me..... but I know nudding.....but if the motor is limited on that mode......how can it reach top rpm/hp ????I rebuilt one......burnt a piston 40 hrs latter,,,, same side as he had probs with fuel tanks......I like carb motors.....simple... like me.