Overhauling my 1988 MerCruiser 4.3 ltr. engine

[Lou C]

I think the Mercarb is a re-worked Rochester 2GV 2bbl carb.
If you want to really wake up that sleepy little 4.3 next time try a Quadrajet, Holley 4160 or an Edelbrock 1409. Of the 3 I am most familiar with the Quadrajet which is such an advanced design it functions as a variable venturi carb and that's why it can be used on anything from a little 4.3 to a fire breathing 7.4. I feel that the 2bbl is OK but the 4bbl is great.
Look at the size of the secondaries on the Q-jet....the small primaries give good response at low rpm and the huge secondaries give it the Quadrajet howl and great top end response.

 

[Rivergator]

Well. this thread is coming to a close. The engine is done. I still have to install the pullies, alternator, starter (both on order), power steering pump and carburetor, which I will do in the next couple of days, except for the carburetor which will be installed after engine is back in the boat to prevent possible damage during hoisting. Now on to the next chapter, the Alpha One drive train. starting with the restoration of the bilge and inner transom assembly before I install the engine. Thanks for all your help saving this basically good but totally abused 4.3 engine from the junk heap, I hope she will run as good as she looks.

 

[Lou C]

Wow that looks great!

 

[Rivergator]

This project is finished and the reaction to this thread has been wonderful. With your help I was able to restore this totally hopeless and neglected engine to its former glory. Here she is humming along just beautifully. Vital statistics are:
Compression: #1=140, #2=150, #3=130, #4=140, #5=140, #6=150. After engine has run for a while I will re-check cylinder #3 and maybe double check valve lash on that cylinder. Timing = 8° BTDC, idle = 700, alternator output 14.3 VDC, oil pressure = 39 at idle, operating temps +/- 130° F. I think we are done with that one. Now the drive goes back on and then it will go in the water for some extensive checking and testing. When I started out I was a total newbie to Mercruiser but thanks to you all I learned a lot and was having a lot of fun doing it (with a few exceptions I must admit - LOL)

 

[Lou C]

Congrats it sounds & looks great.
Comp test results can vary depending on how you do it, engine should be warmed up with throttle wide open.
When I did the cyl heads on mine after the top end rebuild my comp test results were #1 160, #2 160, #3 175, #4 165, #5 160, #6 165
before I replaced the heads they were slightly higher probably due to carbon build up on the old cyl heads
in my OMC shop manual the specs given for the compression test on the 4.3 is 160-175
But if it runs well and doesn't consume oil I wouldn't worry about it.

 

[Scott06]

This project is finished and the reaction to this thread has been wonderful. With your help I was able to restore this totally hopeless and neglected engine to its former glory. Here she is humming along just beautifully. Vital statistics are:
Compression: #1=140, #2=150, #3=130, #4=140, #5=140, #6=150. After engine has run for a while I will re-check cylinder #3 and maybe double check valve lash on that cylinder. Timing = 8° BTDC, idle = 700, alternator output 14.3 VDC, oil pressure = 39 at idle, operating temps +/- 130° F. I think we are done with that one. Now the drive goes back on and then it will go in the water for some extensive checking and testing. When I started out I was a total newbie to Mercruiser but thanks to you all I learned a lot and was having a lot of fun doing it (with a few exceptions I must admit - LOL)

Good job and congrats, glad to see it completed. Get the drive on it and go burn some gas....

 

[flashback]

This Is good news! A great help to all who may follow.