Now Another Water Pump ? 2.3 OMC 1989

[Dasu]

Some of you may have read my earlier post on "what direction " does the thermostat go into its housing. Well I got the thermostat in and all back together. Was running the motor today to test for leaks and all appears good . Thank You . I noticed smoke coming from the water pump impeller cover on the OMC drive. I thought" now what the heck". I shut the motor down and turned off the water to the muffs on the lower unit. I removed the cover plate and could see the impeller internal housing cover was HOT . Waited for it to cool and removed it to find the impeller had no water in there, it was not wet . The impeller itself was wore down a bit and some melted plastic was hardened and seem to prevent the impeller from turning. I have never run the motor without muffs and a water supply. I did install a new impeller late last season and this really helped my temperature problems that were off and on. It worked fine . What could have happened ? I ordered a new cover , impeller, casing for impeller and all gaskets with wear plates . Kind of scared about putting it in and wondering if the thing will just burn this one up. Any suggestions? How can I tell on a I/O if the impeller is spinning? I thought I have heard/read that OMC do not like muffs , some disagree some agree . Which is it? How would one supply water to a I/O if not through the muffs? Thanks in Advance

 

[Scott Danforth]

if the motor is turning, the impeller is turning

you have the muffs hooked up to a hose that is 5/8" or larger and you have the spigot on full, correct? and you did not run the motor over 1500 RPM, correct?

 

[Dasu]

if the motor is turning, the impeller is turning

you have the muffs hooked up to a hose that is 5/8" or larger and you have the spigot on full, correct? and you did not run the motor over 1500 RPM, correct?

In all honesty I did not look at the RPM's . I will say that I increased the throttle a bit to see if I could get the ( new thermostat to open) temperature gauge to move. So I would confess that I ran the engine up one notch from idle. 1500 RPM's , not sure what the RPM's were, I had my eye on the temp. gauge, oil pressure and volt meter but not the RPM gauge. What is the RPM's at idle , do you know by any chance, because if at idle they are 1500 then the answer to your question is yes I ran it over. Hope that is the issue, that it is my fault and not something else. At 71 years old and my first new used I/O , I am starting to question my sanity on the purchase ;-) ! It is a one owner ( I'm second) 1989 Forester 2.3 L Cobra OMC .

 

[Lou C]

Sometimes the muffs do not fit well enough to pump water up to the impeller which is about a foot above the water intakes. I had this with a pair of the dual inlet muffs; the rubber was just too stiff for them to fit well enough for adequate water flow. I tried the Merc/Quicksilver ones with the metal clamp. These work much better and the rubber is more flexible and confirms to the lower unit better.
When you do the impeller you have to make sure that o ring stays in the groove in the housing; it can shift out of place and cause water leaks at the housing.

 

[Scott Danforth]

I have used duct tape in the past

most garden hoses at full blast can only supply most I/O's at just about idle.

 

[Dasu]

Sometimes the muffs do not fit well enough to pump water up to the impeller which is about a foot above the water intakes. I had this with a pair of the dual inlet muffs; the rubber was just too stiff for them to fit well enough for adequate water flow. I tried the Merc/Quicksilver ones with the metal clamp. These work much better and the rubber is more flexible and confirms to the lower unit better.
When you do the impeller you have to make sure that o ring stays in the groove in the housing; it can shift out of place and cause water leaks at the housing.

Thanks for the information! I do have some pretty good muffs and have used them and the older style on outboards before so I am a bit familiar with them. It did appear that they were not leaking around the rubber any as I do check that. I tore into the water pump area once I had the cover off and it cooled . How nice OMC is to make the water pump available to the average guy . The "O ring" was intact and in place. But your point is well taken. I ordered a new complete water pump set and will install that soon as I get it. The out drive was tilted a bit , not much mind you , would that affect the water flow? It was not tilted much , but just another point I need to watch? Just don't want to blow the new impeller out so seeking all the info I can gather. The water impeller that went out was new last year and installed by me and worked very well . I'm thinking there was something in the way I was running the motor ( maybe over 1500 RPM as stated above ) although it was just a bit over idle.Thank You for your suggestions , they are well taken .

 

[Dasu]

I have used duct tape in the past

most garden hoses at full blast can only supply most I/O's at just about idle.

Thank You Scott, I think you may be onto something with the RPM's. That would be the simple fix. I will have to keep an eye on that in the future. We have our own well and the water temp. is maybe 45F+ or - , so it takes a while for the motor to heat up the water to open the thermostat. I may have been inpatient , but seriously did not raise the throttle very much. I value your advice.

 

[Lou C]

the only other thing that can cause water starvation to an impeller is the water tube grommets and the water tube itself. It is rare but the tube can rust through and the grommets can rot and not seal. Also salt water boats kept in the water like mine, can have marine growth building up in the water intake passage, I had to clean that out a few times.

A good test when you have the impeller housing off, hook up the muffs and hold them tight to the lower unit water intake area. Then have someone turn on the hose, the water should gush out of one of the holes in the impeller mounting area....if not....then you have to split the upper and lower and see if there is a problem with the grommets, or water tube.

https://www.crowleymarine.com/johnso...cfm?mdl=MPQPIB
grommets are part 79, tube is 82. They don't usually go bad unless you have a real bad overheat then the lower one can get scorched by the hot exhaust.

 

[Dasu]

the only other thing that can cause water starvation to an impeller is the water tube grommets and the water tube itself. It is rare but the tube can rust through and the grommets can rot and not seal. Also salt water boats kept in the water like mine, can have marine growth building up in the water intake passage, I had to clean that out a few times.

A good test when you have the impeller housing off, hook up the muffs and hold them tight to the lower unit water intake area. Then have someone turn on the hose, the water should gush out of one of the holes in the impeller mounting area....if not....then you have to split the upper and lower and see if there is a problem with the grommets, or water tube.

https://www.crowleymarine.com/johnso...cfm?mdl=MPQPIB
grommets are part 79, tube is 82. They don't usually go bad unless you have a real bad overheat then the lower one can get scorched by the hot exhaust.

Thank You, I'm hoping it is not the tube and grommets. If it is that is maybe above my mechanical level.

 

[froggy1150]

I believe the impeller needs to be lubed during assembly with light lube or something to prevent dry rubber contact damage on first start also

 

[Scott Danforth]

Thank You Scott, I think you may be onto something with the RPM's. That would be the simple fix. I will have to keep an eye on that in the future. We have our own well and the water temp. is maybe 45F+ or - ,

your water temp doesnt mater. you need to have about 10 GPM going out the hose.

 

[Dasu]

Just an update . I installed the new water pump impeller kit in , housing , impeller, o ring (sort of o ring), wear plate and gasket. I really greased up the impeller with marine grease . I took no chances with the "muffs" but dropped the boat in the lake as we live on it and have our own ramp. I got the motor started and the outdrive smoked for a bit but soon let off . I tried not reving the motor any more than idle. I thought I'm going to let this thing run until the new thermostat opens up or the impeller gives in again . The heat gauge began to move to 160, 180, and 200 and then she dropped like a rock and held good . I told the wife I'm taking this baby for a ride . I pushed her a bit on the lake and she ran like a top. Everything seemed fine , I even layed off the back to feel the top casing by the water pump and it seemed good. I honestly can't remember what the heat gauge read all the time on the lake but it was "normal" . Thank You All of Your Help. T