Engine Shakes

[gallma]

OMC Cobra 5.0 L, 220 HP<br />1994 Chris Craft 197 Concept<br /><br />The entire engine compartment shakes. It used to only do this in idle for the first 30 seconds or so, but now the shaking is constant. There is now also a clicking noise that seems to be coming from the right side of the engine that was previously not there. Already had the engine mounts checked, the timing checked, the idle checked, the wood in the bottom of the boat checked, the ignition checked... Have had the possibilities of it being the cam shaft or the crank mentioned--but the mechanic is saying that the entire engine will need to be pulled out and dismantled to know for sure. Any suggestions or advice on this? Or is anyone familiar with the engine shaking syndrome? Thanks!

 

[Boatin Bob]

Re: Engine Shakes

Mine used to shake a bit when it was cold but as soon as it warmed up it smoothed right out, sounds like you have done quite a bit but why not do a compression check, is it shaking like you have a miss in one of the cylinders or is it worse? Do you know if all 8 cyls are firing?

 

[waters]

Re: Engine Shakes

Have you tried this to see if all cylinders are firing<br />with the motor running using insulated plyers or plug wire plyers remove wires one at a time and see if all cylinders are recieving spark.<br />Next remove spark plugs and look at the electrodes they will tell you a lot (oil,too rich,<br />and others check you local library for a book with this info<br />Next check your distributer cap for cracks and wear.<br /><br />Have fun<br />Rick

 

[flashback]

Re: Engine Shakes

waters is right, you are running on 7 maybe 6 cylinders, in any case, the vibes are from the engine. lets try to isolate it. first, pull each plug wire separatly to see if you have a dead cylinder. do this while the engine is running at idle..... if you pull a wire and notice NO difference, then that cylinder is dead. that is the one that needs fixin....... if you pull a wire and the engine slows down and runs more rough , then that cylinder is good........there are many things that can cause this problem, so check the plugs first... replace the plug any cylinder that is dead.....................

 

[russthemuss]

Re: Engine Shakes

The clicking sound is probably one of the high tension (spark plug leads) shorting out.Check em out and replace it.

 

[gallma]

Re: Engine Shakes

A couple things that were done (on a separate maintenance issue) are that the spark plugs were replaced and the carb. cleaned out. Does this rule out any of your suggestions? BTW--the engine shaking is pretty prominent...not just a small quiver. Thanks ya'll.

 

[Bob_VT]

Re: Engine Shakes

Check the integrity of your wires. The shaking can be caused by a simple dropped cylinder. Russthemuss is right, the clicking noise is probably a high tension short from one or more of the wires. <br /><br />If you get the chance run the engine in the dark at night you might even see the short.<br /><br />Another source of shaking is having one or more spark plug wires wrong on the cap.<br /><br />Bob

 

[P.V.]

Re: Engine Shakes

Take you service manual to your mechanic and show him the firing order (proper plug wire on the proper spark plug). He possibly took all the plug wires off at the same time and got two mix'd up ????? Is this a Ford or Chevy?? This is not an internal problem!!!! When in doubt, do a compression check, carb flooding check, timing lite on all cylinders, and cylinder drop test (pull off da plug wire). Since it's a Cobra, have they checked the interrupter switch ???