Hello, all Universal Engine Owners. I have a 1992 Universal M2-12 that i recently had the pleasure of replacing the Impeller for the engine cooling system. I have owned the boat for for approx 5 years and this was the first change out. I thought I would post my experience for other M2-12 Owners. As well as Capri 26 owners that may have an interest.
The day started off as a normal sailing day on Lake Mead NV, Near Hoover Dam. As so often occurs at the lake the wind goes from 0-35 kt gusts on any given day at any given moment, with a constant shift in wind direction turning a casual BBQ cruise into a Gail force wind, batten down the hatches, white knuckled sailing adventure.
After nearly a full day of uneventful easy sailing, the winds picked up, and my friend and i decided to motor in from about 1/2 nm from the Marina. I started the M2-12 11 HP engine and began to beat into the wind at about 5 kts. The engine had been running about 6 minutes when my ever so alert 7 yr old son, advised daddy that there was some smoke in the cabin. I peaked down below and there was indeed a bit of gray white smoke coming from under the stairwell ( engine compartment). I looked at the engine temp gauge and it was pegged on the high end.
IN 3 ft of chop it was a bit too difficult to look at the exhaust and determine if the engine water was circulating or not, in near 35 kt gusts and with a 7 yr old and a non sailing friend on board. The air temp had dropped and it was about 55 degrees outside, I decided to motor in the remainder of the way in instead of cutting the engine and sailing in. I knew that by doing this i risk catastrophic engine damage, by sever overheating.
but the entrance to marina by now was now maybe 1/4nm away. I lowered the rpms and cruised in at about 3kts, hoping the reduced load on the engine would keep it just under the breaking point.
More and more smoke poured out of the engine ( still gray white) as we approached my Slip, I came into the Marina a bit faster than normal anticipating engine failure and then having to coast in, as now the winds had started to die down. I docked the boat , but after a long day on the water ( and a few rum drinks) I determined that I would just check the outside of the engine and the compartment for any obvious damage, and then come back the next day to trouble shoot.
I opened the compartment with fire extinguisher in hand, the heat was overwhelming, but the engine appeared to be ok, NO excessive oil explosion, no belts missing, hoses intact, etc.
I closed it up, packed up and headed home.
The next day I returned to begin the troubleshooting. After looking through the owners manual it appeared the usual cause of overheating on this particular engine was impeller failure on the water pump, which is located in a housing on the front slightly starboard side of the engine. see photos.
Upon opening the water pump cover I was amazed to see what was left of the impeller, it looked like a rounded melted ball of rubber. Closer inspection revealed that the impeller pieces had broken off, and the smaller pieces proceeded up the entire cooling intake hose, into the heat exchange canister., Other pieces had managed some how to flow down the intake hose all the way to the thru hull and became lodged inside the valve at the thru hull intake. See photos. there where also various bits of impeller lodged in ALL of the cooling system hoses, both intake and exhaust. It literally looked like a grenade had gone of inside the cooling system.
Fearing the worst (some type of permanent engine damage) i began removing hoses and unlodging pieces of impeller from the various areas. Luckily I had not one but TWO back up spare impellers on the boat as part of the recommended spare parts kit listed in the Universal m2-12 manual. Installation was fairly easy ( i have the Sherwood version pump) I believe there are 2 other styles made and installed on the m2-12but the sherwood version is the easiest to repair.
After replacing the impeller, flushing and bore punching out hoses, of old impeller pieces i noticed that the rubber exhaust hose leading to the aft exhaust port, had bubbled up and was about to burst from overheating, I went to a local auto parts store found a roughly the same size radiator hose and replaced this as well.
Knowing that the engine had reached critical temperature at one point i assumed the oil would have been burnt up as well. so i took this opportunity to change the oil, oil filter and fuel filter. Im glad I did because the old oil was Black and thinned out to a near water like consistency . I also replaced the engine coolant.
So with fresh oil, new impeller a few cleaned out and new hoses, i crossed my fingers and started the engine. It fired up right away. The temp stabilized even under load, i checked for other siges of damaged from the heat (head gasket) etc that may have been damaged by the but, everything appeared good. I backed out of the slip, went out on the lake and after some slow motoring, cranked her back up to cruising speed. She appeared to run, smoother and quicker than she did even previous to the impeller failure. All in All it was a good experience. And considering I have no mechanical experience or detailed knowledge of Boat engines, i was happy with the outcome.And it was a great learning experience.
My advice if you have, or to avoid impeller failure.
1. have a spare or two on board.
2. have extra coolant on board
3. make impeller inspection part of your bi annual or seasonal maintenance program
4. check all hoses to and from the intake, water pump and thru hulls, for pieces of impeller, had i just changed the impeller it would have overheated again.
5. if the engine overheats check ALL hoses, oil and coolant and replace if needed.
The day started off as a normal sailing day on Lake Mead NV, Near Hoover Dam. As so often occurs at the lake the wind goes from 0-35 kt gusts on any given day at any given moment, with a constant shift in wind direction turning a casual BBQ cruise into a Gail force wind, batten down the hatches, white knuckled sailing adventure.
After nearly a full day of uneventful easy sailing, the winds picked up, and my friend and i decided to motor in from about 1/2 nm from the Marina. I started the M2-12 11 HP engine and began to beat into the wind at about 5 kts. The engine had been running about 6 minutes when my ever so alert 7 yr old son, advised daddy that there was some smoke in the cabin. I peaked down below and there was indeed a bit of gray white smoke coming from under the stairwell ( engine compartment). I looked at the engine temp gauge and it was pegged on the high end.
IN 3 ft of chop it was a bit too difficult to look at the exhaust and determine if the engine water was circulating or not, in near 35 kt gusts and with a 7 yr old and a non sailing friend on board. The air temp had dropped and it was about 55 degrees outside, I decided to motor in the remainder of the way in instead of cutting the engine and sailing in. I knew that by doing this i risk catastrophic engine damage, by sever overheating.
but the entrance to marina by now was now maybe 1/4nm away. I lowered the rpms and cruised in at about 3kts, hoping the reduced load on the engine would keep it just under the breaking point.
More and more smoke poured out of the engine ( still gray white) as we approached my Slip, I came into the Marina a bit faster than normal anticipating engine failure and then having to coast in, as now the winds had started to die down. I docked the boat , but after a long day on the water ( and a few rum drinks) I determined that I would just check the outside of the engine and the compartment for any obvious damage, and then come back the next day to trouble shoot.
I opened the compartment with fire extinguisher in hand, the heat was overwhelming, but the engine appeared to be ok, NO excessive oil explosion, no belts missing, hoses intact, etc.
I closed it up, packed up and headed home.
The next day I returned to begin the troubleshooting. After looking through the owners manual it appeared the usual cause of overheating on this particular engine was impeller failure on the water pump, which is located in a housing on the front slightly starboard side of the engine. see photos.
Upon opening the water pump cover I was amazed to see what was left of the impeller, it looked like a rounded melted ball of rubber. Closer inspection revealed that the impeller pieces had broken off, and the smaller pieces proceeded up the entire cooling intake hose, into the heat exchange canister., Other pieces had managed some how to flow down the intake hose all the way to the thru hull and became lodged inside the valve at the thru hull intake. See photos. there where also various bits of impeller lodged in ALL of the cooling system hoses, both intake and exhaust. It literally looked like a grenade had gone of inside the cooling system.
Fearing the worst (some type of permanent engine damage) i began removing hoses and unlodging pieces of impeller from the various areas. Luckily I had not one but TWO back up spare impellers on the boat as part of the recommended spare parts kit listed in the Universal m2-12 manual. Installation was fairly easy ( i have the Sherwood version pump) I believe there are 2 other styles made and installed on the m2-12but the sherwood version is the easiest to repair.
After replacing the impeller, flushing and bore punching out hoses, of old impeller pieces i noticed that the rubber exhaust hose leading to the aft exhaust port, had bubbled up and was about to burst from overheating, I went to a local auto parts store found a roughly the same size radiator hose and replaced this as well.
Knowing that the engine had reached critical temperature at one point i assumed the oil would have been burnt up as well. so i took this opportunity to change the oil, oil filter and fuel filter. Im glad I did because the old oil was Black and thinned out to a near water like consistency . I also replaced the engine coolant.
So with fresh oil, new impeller a few cleaned out and new hoses, i crossed my fingers and started the engine. It fired up right away. The temp stabilized even under load, i checked for other siges of damaged from the heat (head gasket) etc that may have been damaged by the but, everything appeared good. I backed out of the slip, went out on the lake and after some slow motoring, cranked her back up to cruising speed. She appeared to run, smoother and quicker than she did even previous to the impeller failure. All in All it was a good experience. And considering I have no mechanical experience or detailed knowledge of Boat engines, i was happy with the outcome.And it was a great learning experience.
My advice if you have, or to avoid impeller failure.
1. have a spare or two on board.
2. have extra coolant on board
3. make impeller inspection part of your bi annual or seasonal maintenance program
4. check all hoses to and from the intake, water pump and thru hulls, for pieces of impeller, had i just changed the impeller it would have overheated again.
5. if the engine overheats check ALL hoses, oil and coolant and replace if needed.
