Magnum .52 Four Stroke
03-10-2010, 01:14 PM
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Magnum .52 Four Stroke
I just received a new Mangum .52 four stroke and upon inspection there seemed to be excessive play between the crankshaft pin and rod bushing. I've had many engines, all 2 strokes, and none of them have this much play. I took the back cover off and the play could easly be seen with the naked eye, don't have any way to measure the play but holding the rod and moving the crank there is about 1 degree of play at the end of a 12-6 prop. I have no idea what the proper clearence is for the rod bushing/ crankshaft on this small 4 stroke. Anyone else have one of these with what seems to be excessive play?
03-10-2010, 01:53 PM
#2
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RE: Magnum .52 Four Stroke
Have you run it yet? Was it not running well? Why did ypu pull the back plate to begin with?
The only accurate way to determine "play" or clearance, is to measure the crank pin diameter and measuer the IDof the rod bushing. I'm not sure why you would care unless the engine was giving you problems.
Don
03-10-2010, 02:01 PM
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RE: Magnum .52 Four Stroke
No I haven't run it, I'm almost afraid to and damage it, I'm just asking if anyone else has noticed this and what the outcome was.
Thanks,
michajon
Thanks,
michajon
03-10-2010, 04:13 PM
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RE: Magnum .52 Four Stroke
Idont blame you for openig it up, an inspection of the bottom end is a great idea. After dealing with my Magnum 52 RFS POS!! Iam happy to report they sent me a new one that runs just fine . Was yours devoid of any lubrication too? I had to remedy that situation.
03-10-2010, 06:22 PM
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RE: Magnum .52 Four Stroke
Mine had none or very little lubrication in the bottom end, I could see the rear bearing and it appeared to be dry or nearly dry also. When the weather is nice I'm going to bench run it (before I put it in a plane) and see what happens. One would think the clearance on the bottom end of this little thing would be less than my 429 Ford, but it ain't so. We'll see, I may be too critical.
03-11-2010, 01:50 PM
#7
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RE: Magnum .52 Four Stroke
429, Sweeeet. Love Big Blocks.
In addition, after you give it the first few ounces of runtime Iwould open it back up and flush it out with something like Liquid Wrench to remove the break in particles. You have to inspect the rod anyway right.
In addition, after you give it the first few ounces of runtime Iwould open it back up and flush it out with something like Liquid Wrench to remove the break in particles. You have to inspect the rod anyway right.
