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Old 03-09-2019, 11:28 AM
Ujin Ujin is offline
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Is a Rebuild needed?

I know I need to replace the impeller, but does this corrosion from the, I believe, 502 series water pump suggest a complete rebuild or just a good cleaning?

Also, there is oil between the head and the block on the back of the engine. Exhaust manifold side. Oil looks clean, no water and no excessive vapor in exhaust - small puffs noticed on start up.
Could this be an indication the head gasket is blown?

What are your thoughts?
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Old 03-09-2019, 12:08 PM
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Al Schober Al Schober is offline
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As for the water pump, I can't tell the perspective. Is that the bottom of the pump? Leakage could be the cover plate or the shaft seal. Do the cover plate first - that's easy. If it still leaks, then you'll have to get into the seal.
As for the head leak, keep in mind that there's no oil supply to the head - no overhead valves! More likely that it's a water leak from a stud (or several) that need resealing. The head and manifold studs are part of the water boundary, and a failed stud seal will cause leakage. This leakage can show up at the boundary between the two parts or at the nut on the end of the stud. They can be resealed without removing the manifold/head, but it's often difficult to identify the bad guys.
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Old 03-09-2019, 12:10 PM
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What are the compression test results?

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Old 03-09-2019, 01:48 PM
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First; Great pictures they help a lot!

To me it looks like oil all over the back of the engine from a mist under pressure like an exhaust leak. Common on a two-stroke engine or perhaps a four-stroke with an oil issue. Do you fog this engine in the fall? Even oil up on the head bolts. Is there a crack or bad gasket on the exhaust flange? You can even see the direction of the splatter from whatever source is causing it.

The smell and feel of the oily mess should tell you what it is.

Do you have a carbon monoxide alarm?

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Old 03-09-2019, 01:51 PM
Ujin Ujin is offline
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Yes, that's the bottom of the pump. The water looks to be coming from that weep hole. That may be because of the seal then.

Haven't thought about a water leak from the studs. The studs in that area do have moisture around them. I checked for a water leaks above the engine, but sounds like it could be the studs.

No compression test yet. That's a great though. I will make sure to get those numbers.

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Old 03-09-2019, 02:02 PM
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Yes, that is oil on the head bolt. My though was exhaust too, but there is nothing on the manifold side. It's clean except for the paint coming off and rust. The exhaust flange seems too far aft of the splatter on the block, but there could be a pin sized hole in the manifold itself.
I think my step will be to get compression numbers then run the engine and check for any leaks in the exhaust manifold or head bolts.
There is certainly corrosion inside the manifold as evident from the water pump and coolant line on top the exhaust manifold.

Last edited by Ujin; 03-09-2019 at 02:06 PM. Reason: Additional information.
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