4.3 Gen + with 3 dead cylinders after replacement. Timing?

WBubble

Cadet
Joined
Jul 26, 2019
Messages
12
Hello All!

I have a 1996 Maxum 1900SR with Gen + 4.3.

I did a poor job winterizing her 2 years ago and the manifold and block cracked. Live and learn!

I sourced a used 4.3 from a 2002 s-10 Blazer. Mine is a fresh water only boat. Compression great across all cylinders and the only complaint I had about the "new" motor was quite a bit of sludge inside. I'm running marine accessories, intake, 2bbl Mercarb, starter etc.

Fast forward... Motor's in and buttoned up. I followed the distributor installation instructions in Mercruiser Manual #18. I replaced the fuel/water separator and put 5 gallons of fresh premium gas in.

I've replaced the cap/rotor, hall sensor and plugs with the manual recommended AC Delco's. I bought a new ignition coil at Napa at their recommendation.

I can get her running and idling, somewhat poorly. It appears that my cylinders 2,3 and 5 are dead, however. At a high idle, if I pull plug wires for those cylinders I get zero change. She pops a bit, mostly from the exhaust, occasionally from the carb.

I've moved the distributor one tooth left and one tooth right. I've attempted to get her at 10 degrees before tdc following the base timing procedure.... I cannot get her to run on all 6 smoothly.

Trivia: the fuel gauge showed empty and I think initially I was trying to start her up on an empty tank, so I added 5 gallons of fuel and half a bottle of Sea Foam, while replacing the fuel/water separator.

The crank is spinning clock-wise from the front (left-hand at the flywheel). This is correct, right?

Thanks in advance for any suggestions. From my greater than average experience, she's acting out of time, but if so, I clearly suck at installing distributors and setting timing.
 

WBubble

Cadet
Joined
Jul 26, 2019
Messages
12
Check valve timing...

Thanks! Out of curiosity, if the donor motor ran fine before I swapped the marine stuff, and compression is good, how could valve timing be off? I didn't touch the timing chain.
 

achris

More fish than mountain goat
Joined
May 19, 2004
Messages
27,468
Thanks! Out of curiosity, if the donor motor ran fine before I swapped the marine stuff, and compression is good, how could valve timing be off? I didn't touch the timing chain.

Ok. Most people also swap the cam. You didn't, so disregard my previous.... Use your timing light and check for spark on each plug wire. Also check you have all the plug wires going to the right plugs... It VERY easy to get them mixed up. Check right from the distributor cap.

Chris...
 

WBubble

Cadet
Joined
Jul 26, 2019
Messages
12
165432 clockwise, the easiest thing to do wrong

Thanks. The distributor cap (the old one and the new one), shows that firing order as counter clockwise on the distributor, and the dist rotor moves counter clockwise as the crank pulley turns clockwise using the marine starter.
 

WBubble

Cadet
Joined
Jul 26, 2019
Messages
12
Bt Doctur You're the man, and I owe you an apology! I must have just been assuming the counter clockwise rotation based on the Mercruiser Distributor Caps. I put my eyes on the rotor while the motor was cranking, and.... Clockwise! Fixed the plug wire positions and she's golden!

Thanks also to achris for your suggestions too!

Tomorrow, we water test!
 
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