Engine Needed

[97_Manta_Ray_CR]

Hello everyone thank you for taking a look at my post

I have a 1997 Manta Ray 18' Bow Rider with a Mercruiser 3.0 with an alpha one drive... We took the boat out a few weeks again and I think I have spun a Bearing and now I am in need of a new engine can anyone direct me in where to possibly find a new block for a reasonable price so I can repair my boat and get back on the water soon

Thanks
Chris

 

[Bt Doctur]

Whats makes you think you spun a bearing?

 

[97_Manta_Ray_CR]

The motor is making a ticking sound and ive had a couple of mechanics friends say its a spun bearing

 

[Bt Doctur]

Sure would like to meet these mechanics with X-Ray Vision.
Ticking could be just a slighty loose pushrod, the exaust flappers striking the exaust pipe, or even a bad gimbal bearing. The drive would need to be removed to help isolate any noise.
try posting a youtube video of the noise

 

[boatman37]

there are ticks and there are knocks. usually a spun bearing is more of a knock, but that is a relative term. one way to check for a spun bearing is to pull the plug wires one at a time. but bt doctur is right. a tick can be several things. lifter, rocker, exhaust leak, etc

 

[97_Manta_Ray_CR]

here is a video of the engine in the water making the tick/knock

https://youtu.be/vNeNYNqWWRI

 

[Bt Doctur]

Guessing its a loose rocker arm, outside chance #4 pushrods is loose, may just be a slightly stuck valve too.
You need to remove the valve cover to see if any of the pushrods are loose in the rocker arms.
No need to be putting in a new motor yet.
remove the valve cover, remove the coil wire or the plug/wires from the coil. don't need that sparking .
starting at the front of the motor, hit the key in very quick actions to crank the motor in small increments.
the valves are arranged E.I,I,E,E,I,I,E.
rotate motor until an intake valve goes down and then comes up, this is the compression stroke, feel rocker arms/pushrods for looseness. go to the next cylinder, rotate motor until that intake valve goes down and comes back up, and then the next, etc.
Properly adjusted the push rod will not be able to spin with your fingers.
Post the results.

 

[97_Manta_Ray_CR]

ok thank you for the help I will take a look at it

 

[97_Manta_Ray_CR]

Ok so once I have adjusted the intake valves what about the exhaust valves? What is the order to those?

Thanks chris

 

[DeepBlue2010]

At compression stroke, both valves are closed and can be adjusted together for every cylinder.

 

[97_Manta_Ray_CR]

ok let me start from the beginning of tonight... I took the valve cover off and did like BT Doctur said and rotated the engine till the intake valve went down and then back up and tightened the rocker nut till the rod was just tight and then rotated the engine till the next intake valve was at the up position and adjusted that one too. I guess I should state that all the rod were loose at the up position and I adjusted accordingly on the intake but I know need to know what to do about the exhaust valves. I did notice that now that all the intake valves are tight that the engine is making a rubbing sound as it turns over so maybe I tightened them to tight and they are rubbing on the cam I don't know. I need to know what the right tightness should be on the rods and or the rocker arms..

Thanks
Chris

 

[Bt Doctur]

your supposed to tell us what you found first.
Do not tighten anything until you know what and how much to tighten.Its a good way to start bending valves.
Lets start by backing everything off some , you only want to see about 3 threads above the nut to start.
The cylinders are numbered 1 to 4 starting at the front.
the second rocker arm is the #1 intake valve, rotate the motor until the pushrod comes up and then goes down. The PUSHROD, not the valve.
#1 is now on compression stroke and you tighten the rocker arm nuts until you cannot spin the pushrod with your fingers.
go to the 3rd rocker arm, this is #2 intake, rotate motor until the PUSHROD goes up and then down, this is #2 compression
Adjust the rocker nuts the same way,
Go to #6 rocker, this is #3 intake and do the same.
Then go to #7 rocker, thyis is #4 intak and do the same.