Universal M18 Operating Temp

[drh1965]

Would it be considered "normal" for the subject engine to hit 210-230 if driven to almost 3200RPM? Normally, it hits around 190 when cruising at 6 knots and 2500RPM. We had a wicked current/chop in the seaway this passed weekend and had to crank her up to make decent froward progress. The engine approached 230 but quickly cooled when dropped back to 2500RPM.

I'm planning to pull the HE for some maintenance but was wondering whether 230 is considered overheating/dangerous?

[never monday]

what's the diameter of the HE?

[drh1965]

It is a stock 2" HE.

Thanks.

[never monday]

it's not big enough. Needs to be a 3" in warm waters

[drh1965]

Thanks Pat. Will 230 do damage eventually?

Would you use the 3" for a larger Universal or something different?

[never monday]

small amounts of time at 230 won't kill it. Universal had a service bulletin about the HE sizes years ago. You should be able to get with a local dealer and look up a part # for the larger one.

then again, yours might be crunchy inside and a good cleaning could help.

[jaime_marian]

Hi,I have a Catalina 27 from 1985 also with an inboard M18. The other day, while under power, the engine kind of choked and died, leaving us adrift. I rushed down below and checked the engine compartment only to see coolant seeping (boiling) out the coolant tank cap and out the overflow tube.
Anyone have any idea what this can be due to and how to fix it? I have been afraid to start the engine up again for fear that I will damage it even more. Is it just a matter of adding coolant and starting it again?
Thanks for the help!

[GordMay]

Greetings and welcome aboard the CF, jaime marian.

[sailingjazz]

Originally Posted by jaime_marian

Hi,I have a Catalina 27 from 1985 also with an inboard M18. The other day, while under power, the engine kind of choked and died, leaving us adrift. I rushed down below and checked the engine compartment only to see coolant seeping (boiling) out the coolant tank cap and out the overflow tube.
Anyone have any idea what this can be due to and how to fix it? I have been afraid to start the engine up again for fear that I will damage it even more. Is it just a matter of adding coolant and starting it again?
Thanks for the help!

This is not enough information. There are many things that could cause your Universal to overheat. Most likely would be the sea water impeller failed or the sea water intake strainer plugged. As above in the thread you could also be running at too high RPM. Tell us how you were motoring before it overheated. Was water coming out of the exhaust? Was it the normal amount?

Cheers
Kevin

[jaime_marian]

Originally Posted by sailingjazz

This is not enough information. There are many things that could cause your Universal to overheat. Most likely would be the sea water impeller failed or the sea water intake strainer plugged. As above in the thread you could also be running at too high RPM. Tell us how you were motoring before it overheated. Was water coming out of the exhaust? Was it the normal amount?

Cheers
Kevin

Changed the impeller last December, and before I left, I checked the engine exhaust and everything seemed normal. I was motoring at 5 kts and 2000 rpm for 2 hrs before coolant started to bubble out of the cap. One thing that worried me is that there seemed to be some oil in the coolant tank. The previous owner told me that he had put some oil there in error thinking that it was the oil tank but when I mentioned this to a mechanic in December he didn't seem too worried about it. Should I drain the entire coolant/oil from the cooling system and start fresh? If so, how?

[sailingjazz]

Originally Posted by jaime_marian

Changed the impeller last December, and before I left, I checked the engine exhaust and everything seemed normal. I was motoring at 5 kts and 2000 rpm for 2 hrs before coolant started to bubble out of the cap. One thing that worried me is that there seemed to be some oil in the coolant tank. The previous owner told me that he had put some oil there in error thinking that it was the oil tank but when I mentioned this to a mechanic in December he didn't seem too worried about it. Should I drain the entire coolant/oil from the cooling system and start fresh? If so, how?

If you are sure that you had a good flow of water in the exhaust at the time it overheated then you have another problem. A little oil in the coolant would not be a problem. A lot of oil would be a problem. Another way oil can get in the coolant is if you have a blown head gasket. You could try draining the coolant (there is a block drain on the left side of the engine as you are facing it). http://engines1.novosolutions.net/re....asp?id=59&SID= Then replace the coolant with fresh and try again.

It could be that the oil has gummed up your heat exchanger. If so you would have to remove it and get it cleaned.

I recently had to replace the fresh water pump on my Universal. It locked up so I knew it needed replaced. But, after I replaced it the engine ran about 15deg cooler. If you take off the fan belt and try turning the fresh water pump by hand, it should turn freely. If it doesn't, it may be time to replace it.

Hope this helps. You are going to just need to eliminate problems one at a time until you figure out what is the problem.

I would verify that you have good sea water flow and that your impeller is in good condition and the sea water strainer is not clogged.

Cheers

[jaime_marian]

Originally Posted by sailingjazz

If you are sure that you had a good flow of water in the exhaust at the time it overheated then you have another problem. A little oil in the coolant would not be a problem. A lot of oil would be a problem. Another way oil can get in the coolant is if you have a blown head gasket. You could try draining the coolant (there is a block drain on the left side of the engine as you are facing it). http://engines1.novosolutions.net/re....asp?id=59&SID= Then replace the coolant with fresh and try again.

It could be that the oil has gummed up your heat exchanger. If so you would have to remove it and get it cleaned.

I recently had to replace the fresh water pump on my Universal. It locked up so I knew it needed replaced. But, after I replaced it the engine ran about 15deg cooler. If you take off the fan belt and try turning the fresh water pump by hand, it should turn freely. If it doesn't, it may be time to replace it.

Hope this helps. You are going to just need to eliminate problems one at a time until you figure out what is the problem.

I would verify that you have good sea water flow and that your impeller is in good condition and the sea water strainer is not clogged.

Cheers

Thanks jazz,
Today I hand-pumped the 'coolant' out into a bucket. It looked like a thick, gummy, yellowish, very viscous substance. Then, I unclamped the hoses and dismantled the heat exchanger and cleaned it thoroughly (see pic attached, is the zinc okay by the way?). Still need to clean out the cooling circuit and get rid of all that gunk.
By the way, I am not getting a temperature reading at the instrument panel, what could be the cause?

[sailingjazz]

Originally Posted by jaime_marian

Thanks jazz,
Today I hand-pumped the 'coolant' out into a bucket. It looked like a thick, gummy, yellowish, very viscous substance. Then, I unclamped the hoses and dismantled the heat exchanger and cleaned it thoroughly (see pic attached, is the zinc okay by the way?). Still need to clean out the cooling circuit and get rid of all that gunk.
By the way, I am not getting a temperature reading at the instrument panel, what could be the cause?

OK, viscous and gummy are not good discriptors for coolant. So, getting rid of that and flushing out the cooling system would be good and could fix the problem. There should be a zink in the exchanger but, it is inside and you will have to remove it to see if it is OK. If the temp gauge is not getting a reading the problems could be; low coolant level, stuck thermostat, disconnected wire, bad sender, bad guage in about that order of likelyhood.

[jaime_marian]

Ok, I topped off the coolant and am still not getting a temperature reading at the panel. Could it be a stuck thermostat? I tried to tinker with a wrench to unscrew it but it was stuck hard. Any ideas on how to remove it?

[sailingjazz]

Originally Posted by jaime_marian

Ok, I topped off the coolant and am still not getting a temperature reading at the panel. Could it be a stuck thermostat? I tried to tinker with a wrench to unscrew it but it was stuck hard. Any ideas on how to remove it?

I assume you mean the temp sender which is on the thermostat housing cover. If that is all rusted fast, your best bet is to remove the entire thermostat housing and soak the whole thing in penetrator oil to try to get it loose. First I would ground the wire that attaches to the gage and see if it pegs the temp gage to see if the gage and wire are good. If the gage is pegged when you ground the wire, the gage and the wire are good (likely). In that case the problem is likely either the thermostat or the sender. In either case you will likely need to remove the thermostat housing cover. If you do need to, take your time and use a lot of penetrator oil (watch out it tends to be very flammable).