1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

[GLPmike]

Hello,

We are having a problem with our Volvo Penta I/O b230 engine. We got the boat at auction last year and it run great for 30 minutes or so until it overheats.

When we got the boat we flushed the heat exchanger, installed a new thermostat, new impeller and we still had problems. This year we replaced the water intake fiting on the SP outdrive, but are still having an overheating problem.

Normally when we flush the motor on muffs in the driveway the temp. will climb to 195-200 in a matter of minutes. FYI - When we removed the old thermostat last year the previos owner drilled 3-4 holes in it. So, just for the heck of it when we flushed the engine in the driveway today we removed the new thermostat and the engine did not climb beyond 170f in the driveway after 20 mins at 1200 rpm.

We would prefer to run the boat with a thermostat and we understand its use so we need some help in solving this problem.

Thanks,
Mike

 

[Colliemcc]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

check to make sure the new thermostat is not faulty.

 

[GLPmike]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

Hello,

Yes. We did and the thermostatstarts to open between 188f - 190f. Seems very hot to me for a small engine that tends to run on the hot side.

Is this the correct thermostat for this motor? We bought the thermostat at at volvo penta dealer last year/

Thanks,
Mike

 

[Don S]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

If you are getting 170? with out a thermostat, you have some other problems.
Does it run that hot like that when in the water? Do you boat in salt or brackish water?
When on muffs, Do you plug the secondary pickup (hole in bottom front part of the bullet section of the drive)? This would allow more water to the engine.

Do you get good water flow out of the outdrive when you have full pressure to your hose?
If the exhaust manifold is partially blocked, it will prevent raw water from circulating.
Have you ever checked the heat exchanger to see if it's clean? Not just flush it, but remove the cover to inspect it.
They can become plugged or coverd with minerals that prevents heat transfer.

 

[GLPmike]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

We actually took the heat exchanger apart and cleaned it last year. We run mostly in fresh water. We ran just a few times in salt water and always flush the system after use.

As far as the driveway running, we hook a garden hose up directly to the intake hose in the engine compartment so it feeds directly to the raw water pump. Yes. We do get plenty of warm/hot water exhausting from both hoses and through the lower unit exhaust.

We have never taken the boat out without the thermostat installed. We usually take it out for short runs and once it gets ready to go over 200f we shut it down. Its very frustrating and we believe it was a problem for the previous owner as well as they drill holes in the old thermostat.

Can we use the boat by installing a thermostat that opens at a lower temp. than the 82c/180f thermostat that we currently have installed.

FYI - We were told by a volvo penta tech that these small 4 cylinder engines run on the hot side (170f-180f).

On another note, could there be a problem with the engine's internal water pump?

Thanks
Mike

 

[GLPmike]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

Just found out that there is just one thermostat made for this aq131b/230b engine and that opens at 82c/179.8f.

Someone suggested that we check the oil cooler for a blockage.

Any thoughts?

Your help is greatly appreciated.

 

[captmello]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

I would suggest buying/borrowing an infrared temp gun so that you can confirm the gauge is reading correctly. Check the temp at the thermostat housing. If you have an oil cooler, yes that could be blocked up, as could the exhaust manifold.

has this boat been used in salt water?

 

[GLPmike]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

Yes. It has been used a few times in Boston Harbor by us. Not sure about the prior use. We always flush things out after every use.

I would assume the temp. is high because the engine runs rough and will not start if still hot.

We tested the thermostat and it doesn't open fully until 190f+. by then it's too late and the engine get hot and stays hot until we shut down for an hour or so... This is what the thermostat should be doing to spec., but it doesn't make sence.

Thanks

 

[GLPmike]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

What should we look for to indicate a clogged exhaust manifold?

Just found out that this motor doesn't have an oil cooler.

Thanks

 

[captmello]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

What should we look for to indicate a clogged exhaust manifold?

Just found out that this motor doesn't have an oil cooler.

Thanks

You would have to pull it off and look at it I suppose.

Those thermostats are supposed to open at 190, that seems ok. What doesn't make sense about it?

How hot is it getting?

 

[Robj]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

Mine runs at about 200 - 210 degrees they are designed to run hot

 

[Don S]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

Mine runs at about 200 - 210 degrees they are designed to run hot

Not that hot. 190 to 195 yes, but not over 200.

 

[GLPmike]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

I agree. We let ours get over 200f once and it stalled out. We waited until it cooled down before restarting. Since that first time we are very careful and we shut it down at 200f.

 

[captmello]

Re: 1993 Volvo Penta b230 120hp Overheating Problem - New Thermostat

I would verify my temp gauge is accurate before any further work.