Loss of power, siezed motor??????

[threedunes13]

I have a 1998 2.5 EFI short shaft. Yesterday I was out on the lake for the day, when I took a cutie for a ride I lost power and came to a stop. I tried to restart but the motor was stuck. I tried to turn the motor by hand, it would not turn. After a tow of shame, and some time I was waiting for the trailer and decided to try it again. Of course it started right up and ran good. What gives? I'm afraid to take it out again. Can anyone out there give me some advice. What should I do and or check.

Thanks, Threedunes13

[Rusrog]

I would pull both heads right quick and take a look at the cylinder walls. You will probably see some scoring and some evidence of aluminum on the walls. Your probably not like what you see but looking now will save you big money later....
Also drop the gearcase and make sure that you are not binding there... you probably won't be but I have seen it happen on smaller motors....

Russ Rogers
Ft Worth TX.

[Talon2.5]

well i agree with rus,

if ya couldnt turn the flywheel ya probably stuck it

pull the heads like he said and i'm sure there will be evidence

[AlaskaStreamin]

When my dad's 225 Yamaha seized, it was the lower unit. I diden't realize it till I had the powerhead off. Wish I had dropped the L/U first.

[threedunes13]

Well I finally pulled the heads, #3 has some metal melted to the walls around both the intake & exhaust ports. The heads look fine, no broken rings etc.; I did notice #4 has a small bit of wear right where the piston ring gap is. The motor turns by hand no problem, what I need now is advice. 1: Is there anyway to remove the melted metal from #3? 2: Is #4 the beginnings of loosing a ring locater pin? 3: What pistons should I use, I heard in the past Wisco was making the pistons for Merc. 4: What do you think caused #3 to lean out; I had great water pressure 20+.

I have had so many problems with Merc 2.5's, and I'm seeing a lot of problems posted on this site (and other sites) what gives with Merc. They seem to have a problem with there 2.5's! The last time this motor blew, it was out of warranty by 3 months. After a lot of time on the phone, Merc agreed to replace the power head only, and I had to pay the local shop to install it (that's what Merc made me do) of course there would be no warranty from either the dealer or Merc! The local dealer told me that it blew it because the poor fuel that is in this specific area, he said I would have to run avgas from now on. I have been running ½ avgas, didn’t seem to help, in fact I’ve been reading on this site lately that I should not be running avgas!

I will try to get a hold of a camera and take some detailed pictures of #3 & #4! Is anyone else out there as disappointed as I am in Merc and their products??

Thank you all in advance, threedunes13

[threedunes13]

The motor is basically stock; it has a chip to remove the rev limiter, and a 56-psi regulator. Running pure synthetic oil 40 to 1 and 50: 50 fuel mix of avgas and 92! The motor has very few hours!!!!!!

[Firestarter]

Do not run the AV-Gas, A well set up 2.5 will run a long time. The biggest flaw/problem with the 2.5's is the pistons. I would have the motor torn down and get the pistons staked.
Also if you are running a 56 psi regulator, make sure you are not using a drag box, or you will blow it up again.

as a side not the 39psi regualtors/ecu combos are normally a nicer curve for lake use. (yes even better than the newer A8 and A10)

RT

[dennymac]

if you're running a 56# regulator, you've probably got a drag box that needs the 56# pressure...you need to see which ecu box you've got...if you do have a drag box and a 56# regulator, you must have a fuel pump that is rated for this system...if you have the stock Bosch fuel pump from mercury, it must be #848045-A7, the #848045-A5 is to be used only with the 39# system....if you have the wrong pump, it's a good chance this is part of your problem...the A-5 won't flow what you need....as stated also, the 39# box/chip is a better combo for lake cruising...an A-48 is an excellent choice....if you have a digital box already, the chip can be modified for around $120 to whatever curve you like....dmac

[threedunes13]

Just got done checking what I have,

The stock Pres reg is a gold colored Bosch part # "0 280 160 200"

On the boat black Bosch part # "0 280 160 222"

Stock chip part # "847619-10*"

On the boat chip part # "847619-19"
Below that in smaller print "4390. 11. 500"

Getting to the pump is rather hard, I'll have to get my girlfriend to crawl in and get the part # (it's stock what ever that is). What about getting the scuffed aluminum off of cylinder #3, and piston choice?


Thanks again, threedunes13

[Firestarter]

look on the back of the ECU box, it will either say 11350 A ??, or 849849 A ??, which is it. (or did you just change the chip) Is the back of the ECU box black or gold, all bosch gold regulators are 39psi, all black are 56psi.
As for the fuel pump, it really doesn't matter that much, specially on a basically stock motor, the little pump will still put out 70psi.

As for the sleave, you are going to have to tear the motor down. It sounds like you are going to have to send the block to US chrome to be re- nicked, I would look at sending your pistons out to be restaked, and find out what ecu you are running. I would also at the same time send your injectors to kinsler or RC eng, to be cleaned and flowed, putting the two highest flow on 2 and 5.

Hope that helps.

RT

[threedunes13]

Ok,

I was just given a chip, but the back of the ECU is gold "11350A" then written in pin by hand the number"49", the LAST numbers that I can see on the pump are 580 254 957. Do I have the correct combo of chip and reg? What pistons, and do I need to replace all 6?

Why did this happen, it's just #3, and really doesn't look bad! I know it is impossible to know what happened over the Internet, but I am just so frustrated. The weather is just getting really nice and I am boat less, again!!


Thanks, threedunes13

[Firestarter]

I think that you could take the boat to John Marles he is in or around havasu, he can fix you up, it is best to have somone look at .