OMC guys....check this out:

[dominator202]

I am attaching a few pics of what used to be a #2 on a 1996 3.0 liter 200. After about 300 hours, I went through this motor. I had a light honing put on the cylinders and reinstalled the original pistons after a fine glass-beading. All tolerances were measured and had about .009" clearance on the highest measurement. New OMC rings were installed as well. I had the oroiginal heads shaved .045", and was running Boyesen reeds. Original carbs were rebuilt at the same time to factory spec..."a basic freshen-up". After about 15 hours, this happened. I can still vaguely make out both locator pins in the piston. Wrist pin is blueish in color and this piston is in the condition that I removed it from the motor...appears to be VERY dry.

104435

104436

The other five appeared to be fine. I was running Klotz at 24:1 premix, VRO disconnected. I was turning about 6000 r's when it started acted a bit sluggish, so I let out and it started making some noise. When I let out all the way, it locked up. Appears to be a fuel starvation problem...what do you think?

Thanks,
Matt

[Riverratt]

Why so much oil? Klotz only recommends between 40-50:1 under 8500 rpms to avoid over oiling. I wonder if that was part of the problem. Did you break it in with synthetic also?

[bigbore]

thats a burnup for sure,starvation is a solid guess.or a complete cutoff of fuel n oil supply,96 is definitly caurberated so rebuild carbs,you may find out in the disassembly process that the #2 carb might have something stuck in the main,its depressing but its possible a bowl cleanout coulda been all it needed,also the whole circut of carbs could be running lean,im thinking when you purchase (the boysens)it tels you where to set your carbs,but you still need to do a plug check and,or piston wash check to se how your burning.:cool:

[BenKeith]

That looks almost identical to one I had a carburater to come loose on a few years back, probably started sucking air from somewhere. As it leans out the pistons starts growing and scrubbing the walls, making it even hotter on the sides, that's why you have so much damage down the side of the piston.

[dominator202]

Why so much oil? Klotz only recommends between 40-50:1 under 8500 rpms to avoid over oiling. I wonder if that was part of the problem. Did you break it in with synthetic also?

Yes, I was in the final stages of the break-in after the rebuild. I had previously run 50:1 prior to the rebuild and had never experienced any problems.

Matt

[dominator202]

thats a burnup for sure,starvation is a solid guess.or a complete cutoff of fuel n oil supply,96 is definitly caurberated so rebuild carbs,you may find out in the disassembly process that the #2 carb might have something stuck in the main

I had JUST rebuilt these carbs, and was confident the rebuild was successful. I took alot of time and was very meticulous with this set (as they were going on MY personal motor). After the meltdown, I did disassemble the #2 carb and inspected the main and bowl, but found no contamination. Unfortunately, I didn't pay well-enough attention to ID any air leaks. Other than carb base gaskets and intake bases gaskets, what could have been the source of an air leak? The carb body appeared to still be tight to the throttle body when I disassembled it.

I did talk to a tech at Boyesen before I began the break-in, and he said he would leave the jetting alone, so I took his word for it. Also, if this was a jetting problem, it would seem that the other cylinders would have shown some type of wear as well. I began to blame the VRO, but I'm honestly not sure.

What about the possibility of water in the cylinder?

Matt

[Riverratt]

I am not a guru but I know they say not to break in a motor with synthetic because it does not allow the rings to seat causing heat build up in the cylinder. Some builders also do not recommend double oiling for break in either so I am wondering if the oil mixture was to blame but the next question is why only one cylinder effected?

[dominator202]

I am not a guru but I know they say not to break in a motor with synthetic because it does not allow the rings to seat causing heat build up in the cylinder. Some builders also do not recommend double oiling for break in either so I am wondering if the oil mixture was to blame but the next question is why only one cylinder effected?

I agree w/ you, here. Unfortunately, I recently learned (from a post on this site) that it is a NO-NO to break-in w/ synthetic. I am breaking my last rebuild in now w/ quicksilver.

I don't know if it could be attributed to the oil or not, but I have noticed some rather strange compression readings on break-ins' w/ Klotz before they start to settle down as compared to the one I'm running now, which is much closer to one another than I had previously noticed. Makes sense I guess.

Matt

[Riverratt]

Do you have the motor torn down yet? Is there any major scratching on the other cylinders or just this one? I am not familiar with the loopers real well but did they use the rubber water deflectors between the cylinders? Is it possible one was missing or damaged?

[ken medendorp]

If you over oil the fuel,The fuel is heavier and dosen't flow through the jet's as good causing it to be lean.Plus milling the heads lean things up too. Just a thought.:(

[jphii]

Last time I did that I had a couple of good sized holes in the block. And I broke a big rod into three pieces. Still don't know exactly what happened. Fun, isn't it.

[dominator202]

Last time I did that I had a couple of good sized holes in the block. And I broke a big rod into three pieces. Still don't know exactly what happened. Fun, isn't it.

I have been fooling w/ these things for about ten years and have a collection of scrap aluminum that would fund a third world country for a year!

I got lucky on this one, though. When I felt it get sluggish, I got out of it and, apparently, saved the rod. (I do have some of the H-beam heavy rods in the collection that are twisted into shapes that I didn't think was possible, though!)

There is a small chunk out of the sleeve on the top-side of the exhaust port, but no block damage. I'll bake that sleeve out, and replace it w/ one from one of the blocks in my 'collection' and it should be OK.

RAT: Absolutely nothing wrong w/ other pistons/cylinders. Deflectors are still in the decks as well. Funny thing is that out of all the motors I have seen torched, I have NEVER seen it on #2. After disassembly and inspection, I have absolutely no idea as to what could have went wrong. It is apparent to me that it is dry as a bone and got VERY hot.

Matt

[Lockjaw]

You shouldn't have to change much in the way of jetting for Boyesens, except slightly richening the idle.

You certainly had something go wrong there, and you better find it if you plan to reuse that block and carbs and all that.

Good luck.

[dominator202]

You certainly had something go wrong there, and you better find it if you plan to reuse that block and carbs and all that.

Good luck.

Those Carbs are on the shelf and I am as nervous as a 'virgin at a prison rodeo' to reinstall them. I have several sets of spare carb-sets and I am currently trying to tune a set of big-bores on a late model 3.0 liter. I have another post going a few days old trying to figure them out.

Matt

[Riverratt]

#4 is always my problem cylinder if something is going to happen but mine is a crossflow.

[DBR]

Matt-I am sorry to see you are going through that. We have all been there.I gave up on the plastic carbs in 1988 after alot,and I mean alot of testing. We changed to jet ski carbs and all those problems your having went away. I am sure Gordan or Acie or Stoker has those carbs figured out but they are a crude design compaired to a current race two stroke carb. Fuel injection is hard to beat but on your way to dialing in that you probably will see a few of those pistons.
I know that wasnt any real help but this might be: We would trash that rod that is connected to that burned up piston. It will break through that little oil hole up high after a big sieze like that. Been there. We dont even run the little rods anymore Matt. The gains are nothing compaired to the reliabilty. I hope that helps.

[jphii]

OK Dave, I have to ask: What kind of carbs are you running?

[DBR]

Novi Mukuni watercraft racing carbs. 48mm. They made the same peak power as same throttle body sized injection but not as much overrev. Great carbs.

[dominator202]

Matt-I am sorry to see you are going through that. We have all been there.I gave up on the plastic carbs in 1988 after alot,and I mean alot of testing. We changed to jet ski carbs and all those problems your having went away. I am sure Gordan or Acie or Stoker has those carbs figured out but they are a crude design compaired to a current race two stroke carb. Fuel injection is hard to beat but on your way to dialing in that you probably will see a few of those pistons.
I know that wasnt any real help but this might be: We would trash that rod that is connected to that burned up piston. It will break through that little oil hole up high after a big sieze like that. Been there. We dont even run the little rods anymore Matt. The gains are nothing compaired to the reliabilty. I hope that helps.

That piston and rod are now paperweights. I wouldn't dare put that rod back in after the stress it has endured.

My question concerns the rod?!?!!? Everyone I have talked to MUCH prefers the L/W rods!

Also, I am just fishin' w/ this rig and don't need to have spot-on jetting...I would actually prefer to be a little on the fat side.

Matt

[DBR]

we have carb set up for both stock front 1/2 and taylor front 1/2. Taylor front 1/2 is worth it. We make both intakes. The novi carbs are almost as good as dialed in injection. We have not tried 4 stroke carbs.

[dominator202]

Novi Mukuni watercraft racing carbs. 48mm. They made the same peak power as same throttle body sized injection but not as much overrev. Great carbs.

What would a conversion like this cost?

Matt

[jphii]

You're looking at probably 3 grand + for the carbs. Then you have to make the manifold, linkage, fuel rails, etc.... But they do look cool

http://www.novi.com/images/products/TY-xxXRF-RP.jpg

[DBR]

Matt- We raced and won about 125 rounds with the little rods. After ever days race, each rod was removed and trashed. Almost every rod we ever tuned over 9000 would crack through the little oil hole. The big rods are more than competitive in pro gas and they never break. We have the original 1987 rods in an engine on the dyno right now and they have 200+ 10,000 pulls on them.Great parts. Never break.

[dominator202]

That is an AWESOME looking set of carbs!!!....not in the budget for this year, though.(Or next, by the looks of it).

I would HATE to see the mods you would have to fab to make this work w/ anything remotely like factory linkages!

Matt

[dominator202]

Matt- We raced and won about 125 rounds with the little rods. After ever days race, each rod was removed and trashed. Almost every rod we ever tuned over 9000 would crack through the little oil hole. The big rods are more than competitive in pro gas and they never break. We have the original 1987 rods in an engine on the dyno right now and they have 200+ 10,000 pulls on them.Great parts. Never break.

In that case, I am glad I held onto them! I have about 3 full sets of the H beam rods on the shelf! I never was able to ID what model they swapped to the small rod on? If I am correct, I have procurred 2 different 94' powerheads: 1 with the LW and 1 w/ H-beams, both stockers. You got any idea when they phased these in?

Matt

[jphii]

That is an AWESOME looking set of carbs!!!....not in the budget for this year, though.(Or next, by the looks of it).

I would HATE to see the mods you would have to fab to make this work w/ anything remotely like factory linkages!

Matt

Take a look at their website (http://www.novi.com/)

[dominator202]

Cool site...some good tech info there, but I didn't see anything for our app?

Matt

[jphii]

That's why you have to do a bunch of fabrication to make them work. Somebody needs to talk to them about aftermarket outboard carbs.

[dominator202]

3 grand sounds awefully steep for a 5900 rpm fishing motor, but one more burnt powerhead and I'm spending that anyway! For now, I'll have to try to get these carbs worked out..

Matt

[6Killer]

Will buy most all of the items you need for EFI.

Carbs (even those nice ones) wont outperform EFI and will not be as easy to tune or manage.

JMHO

6

[lokinutz]

Dave, welcome to the boards. Was wondering how long until you started reading and hopefully posting on this site. Now tell Stoner to get back to work!! Damon

[DBR]

Damon-Thanks, Stone is downtairs grinding on a Jasper hopefull project. He grinds during the day,I do at night. It is Fuel injected.......

[racer]

Dave, science project is on the dyno waiting for fuel.

The stock carbs are ok on a stock engine but you CAN NOT have any modifications done and expect to run stock jetting, even a small compression change needs to be compensated for even with efi. As RPM goes up the standard carbs become more of shall we say a challange.

[faztbullet]

Are you doing the cooling mods to this engine?? if not go to mar-fab.com and look at tech bulletin. I looked at your pic's on the carb problem. That midrange jet looks big. When you retest take some toothpicks and plug midrange jet and see if it boggs. Will post a pic on here of a rod I have.





P.s Where you at in Tn??

[bigbore]

Are you doing the cooling mods to this engine?? if not go to mar-fab.com and look at tech bulletin. I looked at your pic's on the carb problem. That midrange jet looks big. When you retest take some toothpicks and plug midrange jet and see if it boggs. Will post a pic on here of a rod I have.





P.s Where you at in Tn??
ITS A V-6 DUDE,i can't say as I know were to go with that:rolleyes:fill me in please (not trying to be a dik)but just kinda wondering how cutting off the mid on 1 cylinder would cause it to bog?1 spark plug going out only shows on top end r.p.m.thats cutting off 1 cylinder completely.

[dominator202]

Are you doing the cooling mods to this engine?? if not go to mar-fab.com and look at tech bulletin. I looked at your pic's on the carb problem. That midrange jet looks big. When you retest take some toothpicks and plug midrange jet and see if it boggs. Will post a pic on here of a rod I have.





P.s Where you at in Tn??

The Intermediate you saw in that 'high-quality' picture is a 30. I am going to try 27's first and turn the idles to about 6 1/2 OUT and see how she does, but will carry some toothpicks w/ me. When I can get it close, I will take a spare set of plugs to the lake see what the mains look like.
When I think back, the very 1st looper I ever had was a 88' model 3.0 that had been severely monkeyed-with, and I remember looking at the intermediates in that carb set and they looked as if they had been plugged 'manually' w/ some type of epoxy. I am on the Hiwassee arm of Chickamauga Lake.

Alan: Other than that reed set, she is ALL stock this time, unlike the one that the above pictured piston came out of. If I get a wild-hair to build a screamer, I'll send it to you next time. All I need is to get this close and reliable...I'm most likely going to sell this rig and I don't want to sell someone a problem.

Matt

[DBR]

Reading this stuff brings back a lot of memories. That is why I have Mercuries on my lake boat. I can't believe I said that but its true. 10 years still running wide open. Never changed a spark plug and dont care. Reliable. It is a lake boat.
My race boat is different. The omc is a challenge, a bit more work than one can imagine to make competitive against the good mercs. I have never Properly thanked Wayne Taylor For reaserching and bringing to our industry the SDS Fuel Injection. Thanks Wayne. I bought the first one made for a two stroke and was pretty competitive with it the first race. For the money this is a great system if you take your time and dial it in slowly. You will never go back to carbs. Good carbs work real close to dialed fuel injection, but you have to dial those in as well. You might as well spend the time and possible damage doing the injection. We have run better fuel injection but it is triple or more money and requires a laptop to map. They can make a few more hp but you are in a whole different world for ease of tunning. All this hot rod stuff is costly, someone said 3,000 gets you most of the parts?...A weldon pump is about 1000,injectors 1000 ........3000 will be there quick. This stuff is a lot. Other fuel injection minus the hardware is 10,000 to get in. Waynes is fair. Good performance for the money. I will be using Waynes SDS at the next race.
If I had a bass boat with carbs I would pay Stoker for his talent. Then I would sell it and get a new Yamaha or Johson and never take the cowling off.
Again, sorry about your engine Matt.

[dominator202]

If I had a bass boat with carbs I would pay Stoker for his talent. Then I would sell it and get a new Yamaha or Johson and never take the cowling off.
Again, sorry about your engine Matt.

Yes, indeed, my first mistake was thinking these things couldn't be any harder than a small-block Chevy....MAN WAS I WRONG. I have learned that the multiple cylinder, 2 stroke marine outboard can do things that cannot be explained!

That motor wasn't my 1st blown PH, which is what brought me to this site. Thanks to some good advice, I am learning!

Matt

[faztbullet]

It was late when I posted. I should have said jets not jet. Yeah.. plugging one carb wont help anything. sorry for the confuzion:)

[bigbore]

It was late when I posted. I should have said jets not jet. Yeah.. plugging one carb wont help anything. sorry for the confuzion:)
I'M sorry if i came off like a dik,thats an easy hypothesis to come to without sorting that reply out.anyway,the carb tunning is something i might end up playing around with this year some,(i aint looking forward to it)the one thing i do know is racer is the man,and when your done screwing around and are still in question,just send it to him,obviously you guys are already bringing up things that make me wanna shy away from tampering with the carbs,i understand that the low speed idle adjustment is its own circut,the mid is its own circut,and high speed is it's own,but when your talking about adjusting one circut and that interphering with the other,it seems like a big task to overcome.i know the loopers had a mid-lean condition(especially during decell)but changing and adjusting the orffices may be opening up a can of worms i don't want to do.i'd like to put boyseens in it and maybe have the heads cut a little but even that's gonna require the complete know how of carb.adjusting.what i'd give to do that for a living and put that knowledge to use evey day.:cool:

[faztbullet]

No harm done... Just all circuits must overlap some to advance to the next stage. I have a set of 200hp carbs (1999) that has never idled right and always had a slight bogg to them:confused: . I bought the boat from the customer after Omc went splat.( He went Black) He had this boat in 3 dealerships in Tn. and 1 in AL. No one could make it idle. I went thru the carbs and did not find anything wrong with them. I installed a 98 year 225 carbs and runs great.Was going to install my V-8 carbs to make a 250hp??but was advised not to.:(

[bigbore]

the situation needs to be done by a know how,thats fer sure,and as weird as it sounds im thinking that mad efi. is probably a good idea,its pretty spendy though,the truth is if a guy looking to make his looper a top contender,stoker could draw a lot of horespower out of it for the money spent on a e.f.i. change-over,taylor marine has got some flashy stuff though,but when it comes time for me to make it run hard the powerhead is taking a trip to stoker.:cool:

[gfinch]

The $$$$ and down time I would have saved by buying Wayne Taylor's EFI system years ago...... Easily 4 times the price of one Total Control EFI system and a MSD ignition system. Don't want to really say cus the wife might see this. Speaking of, factor in having to tell her and having others finding out "Ya stuck another one!"
Another +. Not having to hit the primer any time you back out of the throttle, being able to run at any throttle opening betweeen 5,000 and WOT, without having to worry about lean burning=melt down.
Now all you have to worry about is blowing up the lower unit, because your making too much power,(thanks to Al "racer" Stoker) if there is such a thing. Oh well you can use that as a reason/excuse to go to a short center and a SportsMaster lower.

http://img355.imageshack.us/img355/6791/picture3702wq.jpg

Dave, I still owe you for the reed stops!! I'm glad theres someone sicker than me out there.

[Titan22]

Say Gary, You are always ahead of the game. Now it looks like you have some type of tunner on your exhaust. Must have awlfull fast fish in Ca. Tim

[gfinch]

Tim, it'a not a tuna, it's a SuperTrap muffler for the noise police out here in Calif. Wayne Taylor aka. MadMan made the adaptor to fit my muffler to his center section. As Al said any changes require rejetting !
Do a search,type in "lean burn".
I think both Al and Wayne would help any one out with carb and EFI modifactions. Just remember they make their living doing this!!!

[bigbore]

The $$$$ and down time I would have saved by buying Wayne Taylor's EFI system years ago...... Easily 4 times the price of one Total Control EFI system and a MSD ignition system. Don't want to really say cus the wife might see this. Speaking of, factor in having to tell her and having others finding out "Ya stuck another one!"
Another +. Not having to hit the primer any time you back out of the throttle, being able to run at any throttle opening betweeen 5,000 and WOT, without having to worry about lean burning=melt down.
Now all you have to worry about is blowing up the lower unit, because your making too much power,(thanks to Al "racer" Stoker) if there is such a thing. Oh well you can use that as a reason/excuse to go to a short center and a SportsMaster lower.

http://img355.imageshack.us/img355/6791/picture3702wq.jpg

Dave, I still owe you for the reed stops!! I'm glad theres someone sicker than me out there.
What are you saying now?

[gfinch]

More modifications=more power=more breakage=more$$$=more......

[dominator202]

have access to some good OMC/Bom factory info. Can one of you guys get the OEM jetting specs for a 2000 Johnson 225? I'm guessing it will be J225STLSSA. This should tell me whether I'm close or not.

I took 1 spare set of size 30 intermediates and soldered them closed yesterday. I also changed to the 27 in the carbs on the motor. I will start there, and if that don't work, I will swap to the plugged orfices and see what they will do.

Thanks,
Matt