View Full Version : 2 problems Mercruiser 7.4 bravo 3
06-26-2005, 09:27 PM
For the first time the other day I started my motor and noticed a clicking noise toward the rear( stern side) of the motor left side only. I cant tell where exactly its coming from. According to the dip stick the oil is fine.
2nd- when in netural i hear what sound like a grinding sound when i give it gas in netural it sounds like its grinding faster. Not real loud but if you listen you can hear it.
One more thing. For some reason when i play with my trim tabs i get major powerloss. I cant tell if its an electrical problem or my trim tabs arnt working right.
Any ideas or tips would be a great help
06-27-2005, 05:54 AM
1) Are you sure that clicking noise isn't arcing wiring? Could explain trim problems; 2) Grinding isn't a good sign and sound travels. When was the last time the gimball was serviced? 3) Clicking could be a lifter that won't pump up but that won't help with the trim tabs. If none of the above you'll need to narrow down the possible noise locations.
06-29-2005, 08:20 PM
Get a mechanics stethescope (spelling?) and go looking for the noises to try to narrow them down.
06-30-2005, 08:08 PM
i was listening close today when it was running . It kinda sounded like maybe an exhaust leak. I will further investigate tomorrow. Are there areas prone to leaking with this motor and outdrive??
07-03-2005, 07:00 PM
Well I think it is a valve clicking. What is involved usually to correct a tapping valve. The motor has around 150 hours on it.
07-05-2005, 09:16 AM
It's probably a sticky lifter like Bob H. said. Sometimes they will let loose and pump up. Otherwise, you'll have to pull the valve cover on that side to expose the rocker arms and find the one that is loose. MAYBE, although I doubt it, one might not have been adjusted correctly from the factory, and worked loose. I have also had the pressed-in rocker arm stud start to pull out (everytime you adjust the lifter and think you've got it, the stud would pull out a little more and make it tap again). That would be the easiest fix because all you have to do is tap the hole and put in a screw-in stud. Otherwise, you have to replace the lifter which involves pulling the intake manifold to get to them. If you don't have any mechanical experience, I wouldn't recommend that you try it.