93 Wellcraft 196 SC - Bare hull rebuild

[mickyryan]

if you don't have a thermostat the water keeps recirculating never having time to " absorb heat". water comes in gets hot then gets evacuated for more water to come in get hot, in a car that also gives the radiator time to cool the water before sending it back thru

 

[Patfromny]

You could also have parts of the old thermo stuck in the water passages. Praying that you just need a new one though.

 

[Baylinerchuck]

Sounds like you found the cause of the overheat. Rotted t-stat causing the issues, blocked housing IMO. No t-stat or open t-stat would have quite the opposite effect.

 

[gsxrdan]

Im about to try getting the pump to run from a bucket at water line instead of hose (after priming the hose) and see if it draws water... also hook up timing light and get it close at idle...

 

[mickyryan]

a waterpump on front of engine has no ability to draw it only recirculates

 

[gsxrdan]

a waterpump on front of engine has no ability to draw it only recirculates

yup, but on the VP setups the raw water pump (impeller) is mounted to the crankshaft pulley, also at the front of the engine. (unlike the mercruisers where the impeller is in the leg like an outboard)

 

[gsxrdan]

So the thermostat housing is not at all blocked, and i can blow air/water thru the manifold hoses easily. am thinking maybe a new impeller was not enough and maybe its a worn waterpump housing? am trying to remove the pump now, but it wont budge yet. will research it a bit before resorting to percussive maintenance with a BFH!!

 

[gsxrdan]

pump removed, no BFH needed. the bearing is crusty, the seal is shot, and the cam is worn like a roman coin - i can get a rebuild kit from the states for $150 delivered. no idea yet on HOW to rebuild it tho, mite try my luck searching the VP forum a bit more... if the cam was ok id just try and find a bearing and seal - but then again if the shaft is worn at all (at the seal) its all effed up, and mite as well buy a new pump... bugger!!

 

[Patfromny]

Sounds to me like you've found your problem. The bad seal could have introduced air into the system which hinders or stops circulation depending on where the air pocket it creates wound up. Fingers crossed that you solved the problem.

 

[mickyryan]

hmm that's a bummer, maybe look for a electric water pump? that caN be mounted remotely? then block off where old one went into?

 

[gsxrdan]

hmm that's a bummer, maybe look for a electric water pump? that caN be mounted remotely? then block off where old one went into?

all info i found says not recommended for various reasons. more frustrating is that this pump may not be rebuildable... grrr

 

[gsxrdan]

Ha! take that - 'non rebuildable' water pump!! lol, me an my hammer won this round :evil:

 

[mickyryan]

impeller looks brand new!

 

[gsxrdan]

^ thus my concern with the hot running condition, im not one to run a boat without a new impeller - ever!!

 

[Patfromny]

I'd say between the no thermostat and the timing being off it could run hot. Also if the carb is too lean. The combo of the three could make the engine run hot for sure. Do a compression test and see if the head gaskets are OK. Or throw it all back together the right way, set timing and carb, and take her for a spin. Good job getting the water pump apart. Once again, I'm not up on my IO''s but make sure the impeller is at least touching the sides of the pump. My outboard impellers come out folded over to one side because they are larger than the housing. That one looks straight as a pin. Could be that the fins weren't touching the sides and thus not pumping to their best ability. If they weren't touching, they could actually be creating bubbles which means air pockets , which means steam. I am not an expert but I would think that those impeller fins should have been bent over even a little bit. They make them larger than the pump so they can wear and still work.

 

[gsxrdan]

cheers, but the impeller is brand new (only installed a couple of weeks ago) so hasn't 'bent' to shape yet... and its a very tight fit! will get new bearing and seal today to rebuild the pump (it did have a small leak thru the old seal) also i know it needs a new water inlet housing, this resembles a cars thermostat housing bolted to the leg, and is made of crappy alloy that corrodes badly, could have an air leak there too. since it runs cool on the garden hose at low flow, im sure the issue isnt major, just havn't really had a chance to work on it since it splashed. Thanks for reminding me about compression test tho - forgot all about it! :thumb:

 

[gsxrdan]

done... will get a new pump in the near future - as the body and cam are worn, but this should have us skiing this season at least

 

[mickyryan]

you know shame you cant rig a hone up to just clean up outsides a bit might improve its performance

 

[Carpenter2486]

Been busy trouble shooting! Hopefully soon you will be on the water flawlessly!

 

[gsxrdan]

Thanks Carpenter, gettin there! (as are you, ur build is coming along nicely, shame work gets in the way eh?)