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converting a 5.0 MPI to carbeurator

J

jerry485

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has anyone ever done or has heard of changing over a 5.0 MPI to a cabeurated engine? i am interested in doing away with the ECM & all associated wiring, sensors, relays, etc. go back to the basic engine. something a basic car guy can maintain? any help would be appreciated.
 
Yes,

I understand your anguish..........Motorcycle guys have a lot of the same issues and do convert back to elec ignition but carbed for easier maitanence.

Use this site as a guide and for some parts look up and purchase. look for your engine and year/serial number and do a comparison. If there is no carbed engine listed then go backwards one year at a time until you find the same engine. After a certain year you may have difficulty cross referencing certain parts. IE: standard 305 vs LS1 blocks....

Also incase you have an electric fuel pump and NO mechanical then that also will need to be replaced. The wire harnes, maybe some guages, and some ignition parts replaced or a new marine igniition all tegether, Summit sells a nice Mallory all in one distributor Marine (no external ignition controll module) but you still need a coil.

This is a faily big job and costly to do it RIGHT! If you cut corners and do not make it all coast guard/marine certified/approved then you will be asking for trouble. Just something to consider............
 
if you like fixing things, they make a rinda scan tool and sell the 555 ECM manual # 36, it helps to diagnose problems.
 
I share the disgust for the way the boating industry is going. Just got rid of an old reliable "350" boat for a fancy boat with a 5.0 MPI engine. ..And when I here that if you stop after running for a while, you get vapor lock. BUT that's OK, just add some more things to compensate for that. Believe me I won't go out of radio range. EPA is dictating "Clean" engines and they are great for inland lakes in sight of the shore.
 
thanks all for your help & comments. iam also a little gun shy about going out of lands sight! 3rd time having engine trouble! friends are even a little shaky about going out.
 
EFI is simpler and is pretty easy to work on. A little quality time spent reading the web and trying to understand it will go a long way toward building confidence. Mercruiser stopped using carbs for good reason.
 
I did it. I repowered my 1994 old/tired/overheating 235hp 5.7 to a 2006 Mercruiser 350 magnum (300 hp) which was salvaged out of a fire damaged boat. Some of the wiring got burned and the engine was pulled out, disassembled, and sold to me in pieces as a long block. Oil pan and heads were off and internals looked great. The engine only had 90 hrs. and still had the crosshatch pattern on the cylinder walls. I assembled it and bought a marine vortec intake manifold. I sat the old and new engine side by side and transfered over all the brackets and accessories. I cleaned the carb and bolted it on. I re-used all the old stuff. Starter (1 yr old), distributor, wiring harness, water pump, etc. The vortecs don't have mechanical fuel pumps so I had to get an electric one. I had to rig up a manual choke also. It ran awesome for 2 years and then I sold it. My cruise went from 24mph/2.25mpg with the old to 30mph/3.4mpg with the new. Also with the electric fuel pump and manual choke it started just as easily as any modern car and I could immediately release the choke after it started.

I lowered it in the boat, plugged it in, hooked up exhaust and everything, set the timing, and all was great. I did the whole repower for about $1200 including gas to and from Fl. from NC.
 
baytro23 said:
I lowered it in the boat, plugged it in, hooked up exhaust and everything, set the timing, and all was great. I did the whole repower for about $1200 including gas to and from Fl. from NC.
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that's awesome - I love stories like that
 
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