93 Maxum 4.3 timing issue

suburban99

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Jul 16, 2011
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Bought boat with motor out, installed new head gaskets, intake gaskets, pressure tested exhaust with air. All good. Got boat running, ran ok...impeller in leg was not working replaced...
Boat ran. Installed thermostat as I forgot to when replacing manifold gaskets...Had someone looking to buy and was running boat on a garden hose at idle. 4.3 was reaching operating temp and it quit running...hard to sell if not running.
Since then I have changed the coil wire as coil wire as it was arcing, tried adjusting the timing. Stick my finger is #1 spark plug hole, turn over boat and it seems like I get 2 compressions...
I am thinking the valves may be too tight. Compression tested #1 cylinder and it's a 90 psi.
I have read recently not to spin the pushrod but to try to pull them up and down to eliminate lash. And 3/4 turn after lash is gone. Pretty sure I went to 1-1/2 turns when reassembled. Thoughts?
 

Bondo

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I am thinking the valves may be too tight. Compression tested #1 cylinder and it's a 90 psi.
I have read recently not to spin the pushrod but to try to pull them up and down to eliminate lash. And 3/4 turn after lash is gone. Pretty sure I went to 1-1/2 turns when reassembled. Thoughts?

Ayuh,..... Welcome Aboard,..... I believe yer Right,....
 

alldodge

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Not knowing the serial number, and assuming motor is a 1993

Valve lash is fixed, torque to 20 FT LB and your good. No up/down to mess with
 

suburban99

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Motor is not original to boat. Here's a picture of the intake cover and the tag off the motor...
 

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alldodge

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The tag on the block is the one to use so it is a 1993 motor (not 93 and up). Don't use the 0F that is for a 96 to 97
It does use zero lash (so up/down) and then 1 full turn
 

suburban99

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Removed the left side valve cover and all the rocker nuts are loose...
I set them at zero lash + 1.5 turns when I installed them.
I believe the nuts should be stover style? These have no lock left..

If I set zero lash on #1 at TDC and check compression on #1 I get 150psi.
If I do zero lash plus 1/4 turn I get no compression. Confused.
 

alldodge

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If I set zero lash on #1 at TDC and check compression on #1 I get 150psi.
If I do zero lash plus 1/4 turn I get no compression. Confused.

I'm confused also
I adjust valves by watching which valve is open. If a rocker is opening a valve I do the other. It might take more turns, by I know the other is fully closed
 

suburban99

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I will pickup some new rockers nuts today. They are 8mm-1.0 and I believe they should be self locking (stover style) No?
 

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