Valves on a 1982 140 mercruiser

[THEWHORULZ]

I recently had a new head put on the motor and Im try to figure out which valves are the exhaust and intake. From the no 1 cylinder to the number 4 what are the valves in order. I have a manual but I think its wrong. Also whats the best way to adjust the valves, while its running or adjusting it by rotating the engine 360 Degrees when its not running.

 

[Bt Doctur]

Re: Valves on a 1982 140 mercruiser

E,I,I,E,E,I,I,E
E= exaust, I =intake
Initial setting is to rotate the engine untill a intake valve opens and then closes.That means that cylinder is on the compression stroke and both valves are now closed. you tighten the nut untill you cannot spin the pushrod with your fingers and then go 3/4 of a turn more.Move to the next intake valve and do the same thing. Post your engine serial number and Don s might come along and give you the correct manual .

 

[pilotmsp]

Re: Valves on a 1982 140 mercruiser

I just adjusted the valve lash on my 1989 3.0 4 cyl yesterday. The valve order is a little wacky, but goes as follows: from front of engine #1 cyl- Exhaust/Intake, #2 cyl- Intake/Exhaust, #3 cyl- Exhaust/Intake, #4 cyl- Intake/Exhaust. I would recommend going on YouTube and searching for Mercruiser 3.0 Valve Adjustment. There is a very detailed 15 minute video of a valve lash adjustment. There were differences between his manual and mine of a 1/4 turn when tightening the Rocker nut, but I think it was because my manual has the adjustment being made while the lifters are bled down, i.e. cold engine, and his instructions were to fill the lifters before adjustment. Be careful not to turn the engine over while finding TDC with a remote starter switch or buddy while the fuel line is off, this could lead to fuel being sprayed out of the fuel pump right next to your starter. I ended up turning the engine over by hand rather than reconnecting the fuel line to use the remote starter switch. I caught the fuel in a rag then threw the rag into the driveway to keep the fumes away from the boat. Hope this helps...

Steve

 

[THEWHORULZ]

Re: Valves on a 1982 140 mercruiser

Thanks for the fast response guys. I have one more question which may sound a little crazy...As I mentioned earlier I had the head redone. Now after I have adjusted the valves it is doing the same thing as before which is backfiring through the carb. My guess is on the no 2 cylinder the cam is wore down because the valve still doesn't move very much... Heres my question: Is it possible to buy an oversized pushrod for the second cylinder so the valve can be pushed down further....Has anyone ever heard of doing this? Thanks for any ideas.

 

[Don S]

Re: Valves on a 1982 140 mercruiser

Push rod length has nothing to so with how much the valve opens, that's what the cam does. If you have a lobe off the cam, you need an engine overhaul.Where do you think all that ground off metal went? The bearings are just waiting for the day they fail completely.

 

[mkast]

Re: Valves on a 1982 140 mercruiser

If in fact the cam lobe is worn, using a longer push rod won't make up for the worn cam lobe.
If it's popping out of the carburetor, I'd look at the fuel system.