Card in spokes noise from back of engine
09-21-2015, 11:58 AM
#11
Banned
iTrader: (9)
running the engine with drive off is the best way to separate the systems so you can pin point what side the noise is coming from. Drive side - or engine side.
A real quality doctor stethoscope really helps to. Use this all time even for fuel injectors while running. they can be pricey for a real good one but worth it for what I do day in and day out
A real quality doctor stethoscope really helps to. Use this all time even for fuel injectors while running. they can be pricey for a real good one but worth it for what I do day in and day out
Last edited by BUP; 09-21-2015 at 12:11 PM.
09-21-2015, 12:23 PM
#13
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iTrader: (9)
Will have to read more posts here about whats going on but will throw this out just in case -
ignition Spark arc from either a bad spark plug wire(s) or spark plug(s) itself. or even a cracked coil (possible tower area) ? just a guess at this point
Since you turned killed switch off and cranked over engine no sound ( pulling kill switch kills spark hence no noise)
I would really look at this especially rear plugs and spark plug wires. Especially port side
ignition Spark arc from either a bad spark plug wire(s) or spark plug(s) itself. or even a cracked coil (possible tower area) ? just a guess at this point
Since you turned killed switch off and cranked over engine no sound ( pulling kill switch kills spark hence no noise)
I would really look at this especially rear plugs and spark plug wires. Especially port side
Last edited by BUP; 09-21-2015 at 12:34 PM.
09-21-2015, 01:02 PM
#14
Registered
Thread Starter
Boat had developed a miss a few weeks back. 400 hours so tossed a set of plugs in and boat ran like new again. When I was in the bilge yesterday I double checked all my work from that job. All boots still seated on plugs and the oil line bracket I loosened to gain clearance to get the number 7 plug out was still properly tightened back in place. I will give this area more attention to make sure it is not a spark noise but when I was in the bilge laying in the port side I didn't notice any arcing. The noise more resembles a rod knock than a miss/arcing wire. Best I can tell it is coming from engine centerline back towards inner transom plate.
09-21-2015, 01:22 PM
#15
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Platinum Member
Just something else to throw into the mix . A few years back I had an alignment problem (from new install) that didn't manifest itself until about 60 hours (a 502) .
With the hatch down and idling it would come and go and sounded like someone dragging anchor chain up onto the deck of a tin boat. The coupler went shortly after that .
09-21-2015, 01:22 PM
#16
Registered
Thread Starter
Just seen this, funny you guys throw my name in the mix.
Here is what I would do -
You can take off the inlet or unhook the water inlet cooling hose and hose clamp a water garden hose inside that inlet hose. Turn water supply on and start engine ASAP make sure it pumps water. Of course leave Serp. belt on.
Or take off inlet coolling hose back side of water pump housing and buy a 3 feet to ??? however long hose to connect to back side of inlet water pump impeller housing and either adapt a garden hose inside your hose that you just added or drop that hose in a full bucket of water and keep filling the bucket while engine is running to cool the engine properly..
The testing end here - the outdrive still OFF so take an engine alignment tool and stab it like you are checking alignment - how well is your alignment ??? or is it way off ? next test is leave the alignment tool in and run the engine ? How well of a perfect circle is the engine alignment tool rotation while the engine running or is the circle egg shaped pattern when engine running ?
What kind of shape is your gimbal bearing and U joints ?
have you scanned the engine and looked for available power ?
Here is what I would do -
You can take off the inlet or unhook the water inlet cooling hose and hose clamp a water garden hose inside that inlet hose. Turn water supply on and start engine ASAP make sure it pumps water. Of course leave Serp. belt on.
Or take off inlet coolling hose back side of water pump housing and buy a 3 feet to ??? however long hose to connect to back side of inlet water pump impeller housing and either adapt a garden hose inside your hose that you just added or drop that hose in a full bucket of water and keep filling the bucket while engine is running to cool the engine properly..
The testing end here - the outdrive still OFF so take an engine alignment tool and stab it like you are checking alignment - how well is your alignment ??? or is it way off ? next test is leave the alignment tool in and run the engine ? How well of a perfect circle is the engine alignment tool rotation while the engine running or is the circle egg shaped pattern when engine running ?
What kind of shape is your gimbal bearing and U joints ?
have you scanned the engine and looked for available power ?
Charter Member
09-21-2015, 01:31 PM
#18
*
Platinum Member
Funny you should mention that . A few years ago a friend with a pair of 350 Mags had a slight 'pap , pap ,pap' sound in the engine room when running . In the process of poking around and trying to locate it I smelled exhaust gas , faintly , but it was there .
Feeling around by hand I eventually felt the blowout of an exhaust manifold gasket.
Feeling around by hand I eventually felt the blowout of an exhaust manifold gasket.
09-21-2015, 01:35 PM
#19
Banned
iTrader: (9)
^^^^ will agree with that to exhaust manifold gasket leak.
you need to run the engine with drive off to see the what happens
An alignment tool can pull in and out real easy but when engine running and alignment tool still stabbed the circle pattern will tell you a lot.
1 if rotation pattern is egged shaped - warped coupler mounting, loose coupler, even bad coupler. Loose flywheel, bad gimbal bearing.
U joints that seem butter smooth by hand rotation testing is not a 100 % determining factor that they are good. The true inspection is to pull caps off and look for scaring and needle bearings that could worn as well. Greasing U joints helps to disguises this with hand movement testing. Just went thru this as the U joints felt 100 % great by hand but internal inspection showed a different story. Scaring seen after pulling caps off. Installed brand new U joints - the noise and slight vibration I had went away completely. Just saying and not saying this is your problem but IMO has not been ruled out 100 % either. .
you need to run the engine with drive off to see the what happens
An alignment tool can pull in and out real easy but when engine running and alignment tool still stabbed the circle pattern will tell you a lot.
1 if rotation pattern is egged shaped - warped coupler mounting, loose coupler, even bad coupler. Loose flywheel, bad gimbal bearing.
U joints that seem butter smooth by hand rotation testing is not a 100 % determining factor that they are good. The true inspection is to pull caps off and look for scaring and needle bearings that could worn as well. Greasing U joints helps to disguises this with hand movement testing. Just went thru this as the U joints felt 100 % great by hand but internal inspection showed a different story. Scaring seen after pulling caps off. Installed brand new U joints - the noise and slight vibration I had went away completely. Just saying and not saying this is your problem but IMO has not been ruled out 100 % either. .
Last edited by BUP; 09-21-2015 at 01:50 PM.
09-21-2015, 01:45 PM
#20
Banned
iTrader: (9)
simple to test for exhaust leaks and blown gaskets is with a smoke machine non running engine or run the engine with a portable gas tank mixed with fresh gas and a heavy dose of 2 stroke marine oil. You Will see the smoke of the oil coming thru the gasket leaks when running the engine. Bump up rpms to keep the engine running long enough .
More info - Just saying for carb apps run engine and oil fog thru carb with trans fluid oil or marine fogging oil at around 1200 running rpms. the oil smoke will come thru any gasket leaks hence you found your leaks. Do this all the time.
More info - Just saying for carb apps run engine and oil fog thru carb with trans fluid oil or marine fogging oil at around 1200 running rpms. the oil smoke will come thru any gasket leaks hence you found your leaks. Do this all the time.
