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PD single cylinder issue
http://mudmotortalk.com/mmt_v2/viewtopic.php?f=3&t=28230		 Page 1 of 1
Author:  koonce727 [ Fri Apr 06, 2012 11:14 am ]
Post subject:  PD single cylinder issue
I have a mod'd 06' 36pd thats running on one cylinder. I have gas and spark, and now need to do a leak down. Motor has 40 hours on it since upgrades (bps internals, IM heads, carb)

I am fairly new to the MM world, was wondering if there could be something basic I am overlooking?

I called down to bps, and the main honch was out. The guy I spoke with seemed very iffy on the info he provided me. I was asking him what I should be looking for what I check the compression. I searched the MB forums but couldnt find an answer which led me to calling them. Does the 140 that guy told me sound about right?

Any input is greatly appreciated
Author:  Woodiebuster [ Fri Apr 06, 2012 11:42 am ]
Post subject:  Re: PD single cylinder issue
Probably a valve problem, you need to do a compression check.
It could be a dropped valve, stuck valve, burnt valve you name it.

Pull the valve cover off and inspect that, a pushrod could have came out of the rocker arm or if the valve has dropped you will see that.
Author:  BoatDR [ Fri Apr 06, 2012 11:48 am ]
Post subject:  Re: PD single cylinder issue
1) how do you know it is running on only 1 cylinder? or are you just assuming this because you have a lack of power? If so, what are your symptoms?

2) If you are confident that it is running on 1 cylinder, and you are 100% sure you have fuel and spark, then open the valve cover on the cylinder that you know it is not functioning, and check for a slung push rod, or a rocker arm out bolt that has backed out, or an adjustment bolt that has come loose.

3) if all is good under that valve cover, remove the other valve cover, turn the key on (do not crank up), shift the clutch into gear, and rotate the prop to make sure all 4 rocker arms are all moving up/down the same distance (if not, you have a bad cam).

4) there is a possibility that you have a bad spark plug, so if everything else checks out good try changing the plugs.

5) per the compression, you dont ever look for a specific #, what you want is uniformity in all cylinders (no more than a 10% drop from your highest to your lowest cylinder).
Author:  mizzippi jb [ Fri Apr 06, 2012 12:13 pm ]
Post subject:  Re: PD single cylinder issue
^^^^and this guy knows his chit^^^^^
Author:  koonce727 [ Fri Apr 06, 2012 12:23 pm ]
Post subject:  Re: PD single cylinder issue
Author:  BoatDR [ Fri Apr 06, 2012 12:30 pm ]
Post subject:  Re: PD single cylinder issue
Author:  duckduckboom [ Fri Apr 06, 2012 1:15 pm ]
Post subject:  Re: PD single cylinder issue
Another possibility is that there is a crack in your spark plug boot and it is arcing to the heat shield
Author:  koonce727 [ Fri Apr 06, 2012 1:22 pm ]
Post subject:  Re: PD single cylinder issue
Checked spark the old fashion way by shocking myself. Fuel. I guess I figured since the spark plug had gas on it and smelt of gas, so I could be wrong there.

I pulled the valve cover off. Bare with my poor terminology here. I noticed the lower push rod had fallen off its resting place. The end further in was dropped, but the other end was still connected to the rocker. I then noticed the bolt that holds the lower rocker inplace was loose. Now do I just put it back together and tightin it up? Where do I go from here?

Thanks again for the help.
Author:  duckduckboom [ Fri Apr 06, 2012 1:32 pm ]
Post subject:  Re: PD single cylinder issue
Not exactly tighten it up. You have to set your valve lash. There is a video on you tube that explains it very well. You can search on here, the link is floating around
Author:  duckduckboom [ Fri Apr 06, 2012 1:36 pm ]
Post subject:  Re: PD single cylinder issue
viewtopic.php?f=3&t=27063
Author:  koonce727 [ Fri Apr 06, 2012 1:38 pm ]
Post subject:  Re: PD single cylinder issue
thank you Sir
Author:  koonce727 [ Fri Apr 06, 2012 1:45 pm ]
Post subject:  Re: PD single cylinder issue
Will my valves be the same as a stock motor? or what should I be looking to set them at?
Author:  duckduckboom [ Fri Apr 06, 2012 2:29 pm ]
Post subject:  Re: PD single cylinder issue
I think so but I don't fool with with modded motors much so idk. Boatdr, 50hptiller, or deadbird8 would be the guys to ask that one
Author:  mizzippi jb [ Fri Apr 06, 2012 2:36 pm ]
Post subject:  Re: PD single cylinder issue
take a feeler gauge and set 'em at .005 (both exhaust and intake)
Author:  koonce727 [ Fri Apr 06, 2012 2:37 pm ]
Post subject:  Re: PD single cylinder issue
thank you. I went and purchased a feeler gauge, and just set them back to stock until I get and answer as to what to really adjust them too. I called MB/BPS waiting for a call back.

Even if there are to bet set to stock, they are all very loose.

Thanks again fellas for helping me out. If you were close Id buy ya a case.
Author:  mizzippi jb [ Fri Apr 06, 2012 2:40 pm ]
Post subject:  Re: PD single cylinder issue
.005 is good for most set ups. Only thing that may change is iffin you runnin a cam.
Author:  duckduckboom [ Fri Apr 06, 2012 2:41 pm ]
Post subject:  Re: PD single cylinder issue
Well get me a 12 pack of miller and mail them to me :lol:
Author:  BoatDR [ Fri Apr 06, 2012 3:15 pm ]
Post subject:  Re: PD single cylinder issue
Author:  BoatDR [ Fri Apr 06, 2012 3:16 pm ]
Post subject:  Re: PD single cylinder issue
Author:  BoatDR [ Fri Apr 06, 2012 3:18 pm ]
Post subject:  Re: PD single cylinder issue
Author:  koonce727 [ Fri Apr 06, 2012 3:49 pm ]
Post subject:  Re: PD single cylinder issue
Mine have the Eagle stamped on them. I will set to those specs.

Thank you for the help BoatDR the boat is back up and running
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