I know this is the BIG boys forum, but I need a little help, I sure hope you can tell me. I have been a lurker forever, just never posted.

I have a 1994 Crownline 196BR with a Merc 305 and Alpha 1 Gen 2 Drive.

The boat ran awesome last summer, as it was the first season I had it. I decided since I could only get it to 50, I would do some upgrades over the winter, which were the following:
1) New Edelbrock 1409 Carb- Upgrade from 2bbl Rochester
2) New Professional Products Crosswind Intake Manifold- Same as Edelbrock RPM Air Gap http://www.professional-products.com...uctSBchevy.php

CROSSWIND® for 23° Heads
1957-’95 Small Block Chevy V8

Polished Satin Real Chrome
52025 52026 52022

The new CrossWind Manifold is a special version of the 52020/52021. While it is the exact same height, it features an open area under the plenum chamber. This provides for a flow of cooling air which keeps the temperature of the air/fuel charge lower thus producing more power and torque. The interior plenum and port design are identical to the 52020/52021 and will provide somewhat better overall power than the 52020/52021 due to the special air gap style design.

3) Added K+N Flame Arrestor
4) Had Mechanic change the Impeller in the Lower unit, while he had the boat
5) Replaced Thermostat and gaskets
6) Replaced bent Prop shaft from last outing last summer with drought condtions in NC.

So the problem now, is that it has been running HOT to me. I have not taken it to the lake, but on the Muffs before (merc muffs with the metal rod that goes through the lower) it would not get to hot. Now it is running right at 175 on the Temp Gauge after running for about 15-20 minutes. It is blowing good water out the Exhaust pipes.

I had the Mech redo the Impeller, and it still was overheating, hotter than above. So I then took it apart myself, and I put in all new parts again. This time I changed the housing, all gaskets, impeller, water hose seals/upper and lower. I get good water flow through my Thru hull exhaust, but I am having water leak down and drain out the prop, while it is running. It is not from the hose either, but from somewhere in the Lower unit. The coupler is also brand new on the water tube with all new Orings. I have no switchable exhaust, so there should be no water going out the prop. There is no way for it to get there, as the Pipes in the boat for this are capped off. Could this be leaking through the Weep hole on the housing, and out of the prop? This is the only place that I could think of that it might be coming from. The flow going through the prop is pretty heavy though, like a low pressure hose. So I am stumped. I even pulled the lower off again to check to make sure the Water tube was not broken or bent, and it was good.

Does anyone have any idea on what I am missing?

The thermostat that is in there is a 140 SS thermostat now. I had a 143 Brass in there, and I had tested it in the pot of water. What I don't understand is why the engine is heating up over 20-25 degrees over the 140 Thermostat temp. This is what I would expect it to be about 160-165 which is what it was always at last year. Now it sits just over 175 on the hose. I also tested the thermostats in a hot pan of water with a thermometer and they did open correctly. I think I am going to try pulling the Thermostat out and see what that does.

I have a 6 hose Thermostat Housing, the hoses are hooked up correctly per Merc Manual. My risers are very cool to the touch when its sitting running on the muffs at 1000rpms on the hose, so they are getting cooled no problems, just the block is getting to warm.

Where do I start? I will not be going back to the Mechanic either, he dicked me around as he was stumped on this.

Thanks,
Bryan

aqre you sure your new intake and gaskets all matched up with all water ports, ive seen people put the wrong gaskets on and cover up some water ports.

That is a possibility, but I am not sure 100%.

I did some tests today, and it runs right at 175 or just over on the Gauge but here are all the numbers with the IR Temp Gun.

With the 140 Thermostat in

Left Riser(driver side)- 112
Right Riser(passenger side)-74
Left Manifold(driver side)-170
Right Manifold(passenger side)- 168
Left Block(driver side)-135
Right Block(passenger side)-149
Front of the intake manifold-88
Rear of the Intake Manifold-63
Top of the Thermostat above Thermostat-115
Very top of thermostat housing between riser hoses-55

It took it 4 Minutes to warm up to 175 on the gauge


With the NO Thermostat in but spacer still in place, these tests were taken after the engine had cooled, about 2 hours later. The temp on the gauge barely got up to 140.

Left Riser(driver side)- 125
Right Riser(passenger side)-106
Left Manifold(driver side)-160
Right Manifold(passenger side)- 110
Left Block(driver side)-102
Right Block(passenger side)-102
Front of the intake manifold-69
Rear of the Intake Manifold-75
Top of the Thermostat above Thermostat-93
Very top of thermostat housing between riser hoses-90

Does this help any? I was getting good water flow through the exhaust pipes. I had a buddy of mine outside the boat when running with no Thermostat and he said the water was warm coming out the exhaust when I was idling, I revved it up to 1500 and then it cooled off, he stated.

Do I have a problem, or is this what it should be running with and without the thermostat.

I ran the both with and without the thermostat for over 30 mins and then tested with the IR to get the temps. Does this look normal and I am just being to paranoid.

I also put the lower unit into a huge rubbermaid container with the hose hooked to the lower unit. Trying to see if it made any difference as if it was in the lake. No change in the temps with the Thermostat.

Will it hurt to run without the Thermostat and just leave the spacer in place?

Bryan

I think you've identified the issue, since without the thermostat there is sufficient cooling. There is insufficient water pressure to cool the engine with a thermostat in place.
If you get your water pressure back up to design, your cooling issue will most likely disappear.

I would put it in the lake, as running on the muffs is no real test for overheating. the muffs can let air in and not supply enough water. (really only good for short term running test or flushing of engine.)

It will probably run better and make more power at 175 than at 140. 175 is not close to overheating and shouldn't cause any problem as long as you have good flow throughout.

Exactly.

Muff temps are not really accurate, because the flow can be inconsistent. My temp guages always bounce all over on muffs.

Thanks guys. I will have to give it a shot.

Could the circulation pump on the engine be causing this? I have replaced every part on the lower unit dealing with the Impeller, in the bottom half. Would the gasket that goes between the lower and upper unit cause something like this if it was leaking air or had a bad oring in there for the water to leak or mix air with?

Bryan

Did you install the spacer and t-stat in the correct order?

I had the Oring below the Thermostat, and then the Thermostat with the spring towards the block. Then I had the spacer on top of this.

There was a cork gasket that came with it, but I could not find where this should go from the MERC Service Manual. It only showed the Oring below the Thermostat. The spacer is in there without the Thermostat now and it is running about 30degrees cooler than with the thermostat.

Bryan