Overheating at full speed

[Waterdog ls]

I have had my 1999 outback ls 330 in the shop trick already this year and it my be going back if you can't help me.
I have had the impeller and the thermostat replaced but the boat still overheats at full speed.

What I'm a missing?
They say water is coming through the engine just fine. Is there other places that could be slowing the water down?

Needing help
Thanks a head of time.

Waterdog LS

[Waterdog ls]

Is there a filter I'm missing to check

[sivs1]

is your water pump starting to fail?

[DOCDRS]

Check your tranny cooler for any obstruction if you dont have a water strainer

[Waterdog ls]

I have some one coming over to check the water pump thanks.
I don't think I have a tranny cooler.
If I do were would it be?

[zabooda]

I have some one coming over to check the water pump thanks.
I don't think I have a tranny cooler.
If I do were would it be?

The tranny cooler is in line with the intake hose but if the shop says it is flowing OK then check the gauge connections. What is the gauge reading? Does it fluctuate when on plane or when it is at idle?

[Waterdog ls]

Water pump is bad new one comes on tuesday. Will keep you informed. Plus since the pump is off I will flush the engine in reverse to clear any possible fragments in the engine.

[zabooda]

Interesting, mine failed a few years back but it was making a horrific noise and no temperature fluctuations. Nice that you don't need anything more than an automotive water pump.

[Waterdog ls]

The water pump was bad but it still it over heating.
The tranny cooler what do to it? Flush it out replace it?
Help I'm a bout to shoot this engine

[mmandley]

Shooting the engine will make it over heat.

Several things can still cause your issue.

The trans I am not sure how to flush it but I don't think the bulk of the cooling goes through it, I could be wrong though.

You said the Block flows fine, and the impeller was replaced, I assume the Impeller was whole when it was removed?

Also how do they know the block flows fine? Did they actually flow test it? I am worried you have impeller vanes stuck in it.

Also your exhaust manifolds need to be checked for flow, they clog up and this slows the water exiting and causes it to stay in the engine longer.

Is the boat only over heating under WOT? Will it cruise around the lake normally at say 20-30mph?

[Waterdog ls]

overheats at med seed and full speed.
I pulled the therm out and it was still running at 120.
The impeller was pulled out and it was in perfect shape no missing parts.

[mmandley]

overheats at med seed and full speed.
I pulled the therm out and it was still running at 120.
The impeller was pulled out and it was in perfect shape no missing parts.

I don't understand what you mean by pulled the therm out and it still was running at 120.

Ok well your running out of options.

You have the Impeller that pulls in water, water pump that circulates water, thermostat to hold warm temp, engine block, heads, and exhaust manifolds.

Other then that nothing else the water circulates through.

You can pull the thermostat to see if it over heats due to it being bad. Other wise there has to be a blockage in the block, heads, exhaust manifolds.

Just really isn't that much to the system.

[DOCDRS]

Ok , what does your temp gauge read when it is overheating. follow your intake line until you come to a cannister with 2hoses going to the transmission.......that is your tranny cooler. It may have weeds in it rducing flow unless you have a water strainer before it. If it runs at 120 without the thermostat that may be normal, i really dont know what it should be , but 120 seems reasonable. Maybe you need a new thermostat......you can test it in a pot on the stove with a meat thermometer.

[cornrickey]

When my 86 SN did this the reason was pieces of impeller was lodged in the discharge grate of the pump and pieces when in the hose between the pump and thermostat housing. I only found them after letting water drain from then and finding them in the bilge then found the larger pieces stuck in the pump housing. Good luck

[kaneboats]

Please look at post #1 in this thread and check yours to be sure:

https://forum.moomba.com/showthread.php?22169-Great-Tips-of-the-week-month

[Waterdog ls]

I believe I have the problem located.
It's a electrical issue. When I put the radio on or the bilge, basically any thing the thempature and the oil pressure will spike.
I believe that it is putting electoral resistance on the to meters.
Any ideas?
I'm thinking about rewiring the radio and other add-ons to be connected to the battery directly.