Stupid Move Now Overheating

[stupidhawk]

'78 Scarab with twin 350 mercs. on the port engine i foolishly started it in parking lot this past weekend without muffs and let it idle for 3-4 seconds. Stupid, i know but thought i could get away with it. When put in the water seemed fine but after running hard for 5 minutes or so temp started to climb. Shut that engine down and let it cool for 3 hours or so. When started back up temp rose very quickly and I shut it down again and went back to the trailer with starboard engine only. I figure i ruined one pump in the port engine, is it more likely to be the impeller or the circulation pump? Using muffs, what would be the easiest way to tell which pump is messed up?

Thanks

 

[Fishermark]

Re: Stupid Move Now Overheating

It will be your impeller - not your circulation pump. When you pull out the impeller, make sure all the vanes are intact. If they are missing you will need to backflush the system and retrieve the pieces.

 

[arks]

Re: Stupid Move Now Overheating

Yup-what he said.
And don't do that again!

 

[stupidhawk]

Re: Stupid Move Now Overheating

When i pull it apart what will be the symptoms of a faulty impeller? Does it necessarily have to have broken vanes to be bad? I just really want to do it right the first time and not have to keep taking the drive apart.

 

[Limited-Time]

Re: Stupid Move Now Overheating

There will be signs of heat degradation and it may have taken a set......................the end opposite the input shaft may be melted as well. You will also need to check the housing for signs of heat damage.

 

[ziggy]

Re: Stupid Move Now Overheating

When i pull it apart what will be the symptoms of a faulty impeller?

cracks in the rubber vanes, permanently bent over vanes, or missing vanes. if ya get far enough to look at it. R&R it... if ya have never done the impeller housing. ya might consider doing that too. if yer not sure if it has ever been replaced. heed what fm says too if the vanes are missing.... back flush it to find as many pieces as possible. look at the tstat hosing too. impeller pieces can get trapped there if they've broke off......

 

[stupidhawk]

Re: Stupid Move Now Overheating

Anyone know of a good step-by-step how to guide on the net somewhere to walk me thru disassembly of a pre-alpha drive? I will probably buy a manual as well, but walk thru from someone else would be helpful

 

[Fishermark]

Re: Stupid Move Now Overheating

If you are asking in order to simply replace the water pump, then here you go:
www.mercstuff.com/howdoi.htm

If you are really asking about a total disassembly.... then I don't know.

 

[ziggy]

Re: Stupid Move Now Overheating

Anyone know of a good step-by-step how to guide on the net somewhere to walk me thru disassembly of a pre-alpha drive?

this would be a good thread to read.....http://forums.iboats.com/showthread.php?t=251571 3 & 4 look like they'd cover ya....