Waveline24

BT

Reason for putting that "BE NICE" clause was because I cut an past this message at HOTBOAT and BOATER ED. I know they can be tough on guys over at Boater ed. hehe

Waveline24

I was thinking of just draining the oil and putting in some straight 40w and see where I am at.

What do you think?

OPIE272

My 2 cents worth?
Dump the oil amd put in mercruiser oil. Now you know the oil is capable of doing the job and is not an issue. Troubleshooting is removing the unknowns and analizing the remainders.
Next hook up the garden hose and fire it up with both rocker covers off. Watch and listen for your abnormalities. If you hurt the engine running it at the lake, idling in the driveway won't do any more damage that you have not done already. If you collapsed a lifter of flattened a lobe on the cam it will take the same fix if it's a little flat or even gone. The fix is the same.
Don't worry, &&(&*%^(&^ happens. And if any one says it's never happened to them they are either just getting started or are pulling your chain

ragtop409

Wave, that sound good I run Kendall GT1 strait 40 in my 7.4L here in seattle and a FRAM HP4 racing filter I know these to items wont let you down. Go to Action Auto change the oil filter and fire it up on the garden hose. So your neibors can enjoy your boat to. Charlie

GO4BROKE

I agree, use stock Merc (25w40 I think) and re-asess the situation. Save the fancy oils for when you have the problem figured out. Anything that reduces the number of variables to a problem is the right path. Its called "strategy based diagnostics" for those that must be pc.
When its all fixed, I like Mobil 1 15w50. 5 years no problems with the oil.

Vinny P

Waveline24;

What do you mean by " Could this be a rocker arm making noise even though they are all still torqued at 40LBs? "

Rockers don't get torqued down, they get adjusted to different specs depending on what type of cam you run. Are you talking about the rocker studs? If so, they should be torqued. Adjusting rockers properly is critical to the life expenctancy of the cam and lifters.

Waveline24

Checkmate,

I am referring to the rocker arm bolts. Specified in the Merc Fact Manual to torque to 40lbs Ft.

blue thunder

Gen V and Gen VI engines do indeed have non adjustable valve trains and use a shoulder bolt torqued to 40 ft-lbs to center the lifter plunger within its stroke.

Mark IV engines have the stud with the nut that needs to be properly tuned. You must have a gen V Waveline.

BT

SeaRay Jim

Could be a long shot, but if you just rebuilt it, new parts? New lifters? Could you have a colapsed lifter? Woudn't be the first time a new lifter colapsed.....

rjcardinal

While you have the valve cover off look very closely at the valve springs. Inspect for a broken spring. The inner spring or damper on some 7.4's are prone to breaking and its hard to see.

Good luck and post what you find,

Ron