OMC 4.3 Cracked NEED ADVICE Maybe 4.3 fuel injected??

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kalisto2k1

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Hello,<br /><br />I have a Edson boat that I purchased with a cracked 4.3L block. It's a 1989 OMC cobra. The engine is toast and has to go, it knocks really loud. I was wondering if I could put in a newer fuel injected motor from a GMC jimmy or blazer?? I can get a low miles motor with computer and all wiring. Will the OMC manifolds bolt up to the block? What other modifications are involved? If you guys can help me out I would greatly appreciate it.<br /><br />Thank you<br />Mike
 

WillyBWright

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Re: OMC 4.3 Cracked NEED ADVICE Maybe 4.3 fuel injected??

Welcome to iboats.<br /><br />You can't use an automotive EFI on a boat. They require a return line to the fuel tank and that's a big USCG no-no. You can use the base motor, but almost everything attached to it has to be marinized or you risk an open-water explosion. No big deal since you already have all the stuff you'd need on the old motor including the camshaft. But an automotive EFI in a boat? NOPE!
 

Bondo

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Re: OMC 4.3 Cracked NEED ADVICE Maybe 4.3 fuel injected??

You'll Also run into Issues with going to a Newer Motor.......<br />There have been At Least 3 Different 4.3l series......<br />You'll need to find a block that Matches the 1 that's cracked.......<br /><br />Early motors had a place to mount a mechanical Fuel Pump........<br />Mid-motors Lost the Fuel pump boss,+ have a 3rd shaft, the Balance shaft, mounted above the Cam.......<br />Late model motors are of the Vortec family.........<br /><br />A Truck motor of the right Vintage IS the best place to Start,...... <br />But, As stated by Willy,... Automotive induction systems Are a No-No.......
 

kalisto2k1

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Re: OMC 4.3 Cracked NEED ADVICE Maybe 4.3 fuel injected??

Hello,<br /><br />Thanks for all the advice guys!!! So I should be looking for a scrap yard motor right? I'm guessing 87-90?? Where would I find the numbers on the blocks. Because all I need is a block since all my other parts are good right?? My original motor had 90 hours of use on it. Everything including the crank looks tip top.<br /><br />Thanks for your help<br /><br />Mike
 

Bondo

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Re: OMC 4.3 Cracked NEED ADVICE Maybe 4.3 fuel injected??

Mike,....<br />I'm not sure When the changes occurred,...<br />But the Differences are Easy to See, from the outside.....<br />As Long as your "New" block is the Same as your "Old" block, You'll be good to go......<br /><br />87 to 90 Sounds Right,... just Look to see if they both either Have or Don't Have the fuel pump boss....... No #s Needed...
 

KaGee

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Re: OMC 4.3 Cracked NEED ADVICE Maybe 4.3 fuel injected??

IF a cracked block is all that was wrong, yes, just have a machine shop rebuild a motor from your parts and another block.<br /><br />You mentioned knocking... that troubles me... please expound on that a little more. A cracked block from freezing or overheating??
 
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