1998 Offshore efi 200 .... Blown

M

mke039

Seaman
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Jan 4, 2010
Messages
69
Hi all, just bought a gorgeous 231 Mako for $4K...why? Cause the 200hp efi offshore Merc is "blown". I am sitting on my ship now in AK (had the wife and brother-in-law get the boat)...and am wondering if changing out a piston is difficult. I just bought an even sexier Seacat with twin Honda 50's for $2K...why? Cause the dope managed to flip it and submerge the 4 strokes. I was able to rebuild the Hondas (full of saltwater) and had to replace one piston. They fired up fine.
Anyone rebuild a "blown" Merc efi offshore before? Also what does efi stand for? Is it fuel injected? Then why the carbs...
Any pontification on these engines will be read closely...I ordered the service manual but obviously have not seen it yet.
And yes...I have plenty of time on my hands here. If you have some on yours I would love to hear you input.
Thanks!
 
M

mke039

Seaman
Joined
Jan 4, 2010
Messages
69
Re: 1998 Offshore efi 200 .... Blown

Oh...where is a good place to buy gaskets, carb kits ect? I looked on ebay but no joy.
 
Faztbullet

Faztbullet

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15,620
Re: 1998 Offshore efi 200 .... Blown

Anyone rebuild a "blown" Merc efi offshore before?
Click to expand...
Yep....usually all 2.5's that pop needs boring or resleeving.
Also what does efi stand for? Is it fuel injected? Then why the carbs...
Click to expand...
EFI stands for electronic fuel injection and if it has 3 carbs its not fuel injected and you've been suckered ...
 
M

mke039

Seaman
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Jan 4, 2010
Messages
69
Re: 1998 Offshore efi 200 .... Blown

Mako engine.jpgNo, I have not seen the engine yet except for this pic...

I was trying to learn as much as I can so that when I get home I can get to work on it.

Are there sleeves in the block now? Are they simple to change out?

Thanks
 
M

mke039

Seaman
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Messages
69
Re: 1998 Offshore efi 200 .... Blown

Shoot...stripping it down to the bare block and heading to the friendly machine shop IS my idea of DIY
At least the part where you put it all back together.
Do these things get pressed out, banged out or screwed out?
 
Faztbullet

Faztbullet

Supreme Mariner
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Re: 1998 Offshore efi 200 .... Blown

Do these things get pressed out, banged out or screwed out?
Click to expand...
None of the above...I cut em out with die grinder, cut a slit down the middle and snatch em out with slide hammer. takes about 10 minutes with proper tools. Takes aabout 5 minutes on a 2.4 block as sleeve doesnt not go all the way to bottom of cylinder. Before you start spending money on block repair you better send the ECU and injectors off to Brucato and have tested as if ECU is bad an caused it to pop that a $1400 bill before you even fix the block.....
 
M

mke039

Seaman
Joined
Jan 4, 2010
Messages
69
Re: 1998 Offshore efi 200 .... Blown

I plan to send the injectors and ecu out to them.
I just got home and they were not kidding. The port side head is off (and missing) and the bottom piston is liquid aluminum. There is aluminum slag coating the liner.
My question....I found a 96 Merc 150 EFI for sale that is blown. Are engine parts....ecu, injectors and HEAD interchangable?
 
Faztbullet

Faztbullet

Supreme Mariner
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Messages
15,620
Re: 1998 Offshore efi 200 .... Blown

If the 1996 150 is a 2.5L parts will interchange except the block as its ported different. The ECU will not work as it has a different fuel curce programmed.
 
cajunmerc

cajunmerc

Cadet
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Oct 14, 2011
Messages
25
Re: 1998 Offshore efi 200 .... Blown

The 231 mako will have a 25" transom, thus the 200 offshore is likely gonna be correct length for the boat, a 150 efi would be special order w/25" mid, likely a 20". You could use the 150 powerhead on the 200 midsection.
 
M

mke039

Seaman
Joined
Jan 4, 2010
Messages
69
Re: 1998 Offshore efi 200 .... Blown

Thanks for the awesome replys. I ordered a piston, rings and heads off ebay, and think I will pass on the 150. It is blown too and I have enough to do with this Merc and two Hondas I am rebuilding. I just got one honda done today, except the carbs which I want to go through. I am waiting on Merc gaskets and that darn head.
I have read really great reviews on this Merc....except for their thirst for gas...so thanks for the needed info...this site is the best!
 
M

mke039

Seaman
Joined
Jan 4, 2010
Messages
69
Re: 1998 Offshore efi 200 .... Blown

Regarding Honda carbs, bought em off craigslist as both submerged carbs (both engines) were beyond repair....when in doubt.....rebuild your carbs!!!
I had gotten this engine started so I was going to dismiss the carbs....except the top carb had leaked when I pumped them up.
Wow...the supply line was totaly clogged with junk. The float needle was not seating because of this.
I would have cooked the piston quickly.
 
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