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over heating problem

M

micmac117

New member
i have a volvo penta 4 cyl a125 that over heats when i get up on plane and running
trolling it is fine
i testedthe thermostat and it is fine
it may be the heat exchanger is it possable to remove the heat exchanger and let lake water cool the motor if so what do i do

thanks mike
 
Mike, many over-look the water neck fitting when this issue arises.

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This is the part that attaches to the main suspension fork, and connects the S hose to the water supply.
These are to be considered a "wear item" and should be routinely replaced.
This part also comes up and out of the water when on plane.... and would explain why you are not having this issue when going slow.

Great time to replace your drive shaft bellows, and perhaps pull the PDS and replace the single bearing.
If you need a shift cable, you're right there in this area also.
Any of these are much easier to do with the transmission off and out of your way, IMO.

Kill several birds with one stone!

NO.... you do not want to remove the heat exchanger.
Your engine is not designed to operate on plain water or sea water.
These work very well when all else is up to snuff.

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so this fitting,it is on the out drive that has a hose attached to that that goes down into the botton end of the outdrive
is this something that anyone can do that is a bit mech inclined or does it need to go do a dealer
a dealer told me to run the boat with out thermostat to see if there is a blockage is that ok to do
 
http://cgi.ebay.com/Water-Inlet-Hos...at_Parts_Accessories_Gear&hash=item53e7cd12baAll these 4 cyl. Motors tend to run hot with out a thermostat,you don't want to rig a radiator on here either.yes, it would be a cheap fix with used parts,but i don't see it working,your not gonna get the air flow through the radiator like you will on a car even with the fan,the engine in your boat also runs long periods at a much higher rpm than what a car does,so it needs that constant cool water flowing through the heat exchanger to keep it cool,also with out water flowing through your exhaust manifold you will melt off the rubber boot that connects the manifold to the pipe in a matter of probably 5 minutes,inless you plan on running the exhaust straight through the transom?the thermastat can be purchased at an auto parts store for around $5.00 to $8.00 tell them you need one for a 78 volvo 242 4cyl.get somewhere around a 170 degree one thats what i have and keeps my engine around 193degrees, replace the water neck,it's fairly easy to do,i've replaced mine without removing any other parts,as long as your 2 allen bolts are'nt severly coroded?you may be able to find one old stock on ebay cheap?if that still does'nt cool it down another problem i've experienced is open your heat exchanger and remove the core,the small passages on it can become clogged and cause poor water circulation,spray it throughly with a stong spray nozzle on your hose,or a pressure washer.also check the impellar on your raw water pump and make sure you don't have any damaged or missing blades on it?attached pics. Of clogged core from an aq 125 exhanger.*******inserted link at top of page for water neck with gasket on ebay for $30.00 4 availiable********
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