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Guest dma251

Motor shut off and won't crank now - seized?

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Guest dma251

I had a great weekend, until this happened...

I was taking a fairly modest 70 mph run down the lake, when I trimmed down to turn around, and mid-turn the motor died. Trying to restart, it acted like the battery was dead. I got a couple of cranks out of it, and then no rotation at all. Pulled the battery, charged it for a couply hours, and still nothing. It tries to crank, but no engine rotation, just a bark out of the starter. I am fairly certain the starter is engaging, but either i have a very bad battery, or a seized engine, I suspect.

I am home now, and haven't looked at it yet, but I am very concerned. I just bought this thing. I was absulutely RELIGIOUS in my oil mixture - 32:1 Pennzoil Synthetic, and 91 octane premium. I hadn't run it very hard all weekend, as I am just getting started. I hit 94 mph once. That's it.

If I pull a head off, do I have to replace the head gasket with a new one? Assuming the worst, I had a seizure, what am I looking at to make it right again? I am pretty mechanical, and have rebuilt plenty of car engines, but this is my first two stroke. It looks pretty simple, and I have a factory manual. How much are parts to do this? Sleeves?

THIS SUCKS!!!!!

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Start by pulling the spark plugs to see what they look like. If they all look the same then drop the lower unit, and then try to crank the engine over by hand. If one of the spark plugs looks way different then pull the heads. It should turn easy with a wrench on the flywheel. If it doesn't then pull the heads. The big question once the cause of failure is found is to find out WHY it did it! Please post some pictures once you get it apart.

I just did a re-ring on my 300PM which was my first OB rebuild and all went well. Just follow the manual. I'm also a pro mechanic for VW/Porsche/Audi and the OB is simple design comaprted to some of the engines I have had to repair.

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If the engine looks OK after you take the heads off but still won't crank, look at the gearcase. I have had many guys bring their stuff in to find the upper driveshaft or pinion bearing seized. Drop the lube and see if it is contaminated. Good thing is the gearcase costs less than the powerhead to fix. Just some info just in case.........................

Randy

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Guest dma251

Well, I pulled off the heads today - I'll post some pics tonight. The cylinders looked okay, except for some carbon built up on the pistons. I could BARELY turn it over with a ratchet on the flywheel.

I dropped the lower unit and VIOLA!! A freely turning engine!

So...... What do I do with the lower now? I am actually much more comfortable with working on the engine then I am with the lower.

Can I reuse the headgaskets?

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If the engine looks OK after you take the heads off but still won't crank, look at the gearcase. I have had many guys bring their stuff in to find the upper driveshaft or pinion bearing seized......

And how. What he said. I'm one of the many guys. Thought I poofed my powerhead over Memorial Day weekend. Turned out to be the gearcase. Randy rebuilt it Memorial Day Monday while I waited. Now THAT'S service. biggrin.gif

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How does the gear fluid look? Any metal shavings? Or CHUNKS?

You MAY have only damaged the top bearing. If not, it may be cheaper to replace it than to fix it.

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Guest dma251

I didn't even check it - just pulled the unit and drove it into the shop. Whatever it is, I'm not gonna be able to deal with it, and to tell you the truth- I'm so relieved that it's not the powerhead I am happy to pay for whatever it needs.

Wayne, motor issue or not, your old boat feels just awesome! The previous owner didn't exactly keep it the way I would, but it's safe and sound in my garage now, and I got her looking as close to new as possible. Your innertube is still in the bow, and your ballast shot is still in the port sponson! I had it up to 96 this weekend, and considering it was on a 26 ET I guess that's pretty good. Except when it's grenading the lower unit it runs sweet! If anything, I am a little intimidated by how light the boat is - makes me a little worried about getting airborne...

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