Replace just impeller or housing also?

[jdamron]

I have a force 120 (1995?) outboard that I am attempting to get into shape. When I test ran it on a lake a couple of weeks ago I know I saw water flowing out of the cooling water outlet from the bottom crawl. But the other day when starting it up in yard with water muffs I did not see any water flow from the upper crawl - there was just a dribble of water coming out. I did find warm water exiting from the propeller.

So I removed the lower unit today and took apart the water pump. I can see the impeller is really warn but I do not see any large missing pieces. See pictures below. I was just wandering if this wear is enough to affect the water flow that much. Also I was wondering if based on the condition of the wear plate and housing if anyone has any opinions if I should replace using a full kit that has new housing and backing plate or just get a new impeller and gaskets. It seems from the research I have done so far it is not that much more to get a full kit instead of just the impeller and gaskets.


Oh one other question - is the fitting above the thermostat cover some sort of back flush connector? See picture below. I was thinking of trying to back flush while lower unit is off to see if anything comes out. But I can't find any reference to what that connection is and it does not seem right size to fit a water hose. Thanks in advance for the thoughts.

 

[wickware]

Re: Replace just impeller or housing also?

1. I could not see any damage to the water pump.
2. I could not see enough damage to the impeller to not get the previous water flow.
3. I feel the muffs will not give you the fit or Etc the Lake or Deep 55 barrel will unless you fit or tape them well. I still question if the muffs force water through if the impeller is being tested vs forced cooling water???

 

[Jiggz]

Re: Replace just impeller or housing also?

You need to replaced that impeller now since you are already on it. As for the housing, I do not see any apparent damage except for rubber stains which you must clean thoroughly. The housing must be shiny clean all over. As for the thermostat housing, no there is no such thing as back flush connection instead it is probably a water pressure or tell tale connection, unless somebody made some modifications to it.

 

[jerryjerry05]

Re: Replace just impeller or housing also?

Wick??? Time for new glasses!!
That impeller is about as bad as I've seen and still have the vanes still attached??
The vanes should be straight out from the center.
The stainless plate should be smooth all the way across.
The same with the impeller housing.
It will work with some grooves but should be smooth.
The thingy on top is probably a tell tale someone cut back.
Buy the whole thing.Gasket,plate housing.
When using muffs?? Make sure it's sealed real good.
If I'm in doubt?? I use duct tape and seal it good.
Running in a bucket??
IT needs to be DEEP in the bucket at least 2-4 inches over the cavitation plate.

 

[wickware]

Re: Replace just impeller or housing also?

Jdamron, Can you send pics in better light if it?s not too late. I tried to add light to the pics to justify Jerry?s observation. Most of all, did you see rubber cracked or missing from the impeller bad enough to affect the flow? Did you see wear marks that were deep enough to stop your fingernail from sliding across them?

1. I tried to see if any rubber was cracked or miss vs bent which is normal after the impeller is used IMO.

2. I tried to see any deep wear that would justify a new housing but c/n with the lack of light in pics.

3. Once the impeller is pulled with age on it, it?s always a practice to replace it. Approx how old is the impeller?

4. Attached is an impeller I used from 1985 -2009, to show it was not cracking and flexible (with metal lodged in) or missing rubber and I w/n do again. I feel the qualities of impellers are not the same today. This impeller saw 3 summer months use in fresh water only, 6-7 short fishing trips approx 5 miles a trip at the most. Ugly and Lucky Me!

 

[Jiggz]

Re: Replace just impeller or housing also?

I do not believe there is any need to repost pics of the impeller. The fact that there are rubber stains and the vanes have chipped ends and you already have the thing opened, there is absolutely no reason not to replace the impeller and to clean and smoothen the housing. Unless of course you just love to do this kind of thing (opening and inspecting) more often than required.

 

[jdamron]

Re: Replace just impeller or housing also?

Thanks everyone for the feedback and ideas. I have only had this boat and motor for a few months and unfortunately I do not know the service history. I have been slowing trying to go through things and fix what I can. Based on original feedback above I was considering ordering just the new impeller and gaskets to save a few bucks as the metal housing seems like it can be cleaned up. However, this morning I was cleaning up the plastic base (cover assembly) that the metal backing plate sits on and I found lots of bumps in the plastic. See picture below. So I am just going to buy the complete kit. I am afraid with these bumps in the plastic I will not be able to get a good seal. And it looks like the kit 43024A7 coves with this plastic cover assembly.

Also one other related question. I was cleaning the main lower unit surface that the plastic base is attached to in preparation of the new parts and noticed if I turn upside down the unit to rinse of that I get some drips of gear oil out of that center cavity. Is this normal? I am assuming that when the new gasket and plastic base is installed it will keep the gear oil in and the water out but I wanted to double check. Should I pack that cavity with grease when installing the new plastic base? Here is a picture:

Also, here is a little better picture of the worn impeller as requested:

Thanks.

 

[Jiggz]

Re: Replace just impeller or housing also?

If money is not a concern (which it sounds like it is) try replacing the impeller at the very least and then followed by its housing. As for the rough surface on the plastic, if you cannot afford a new one, you can still smoothen it out with a fine sandpaper and will still be usable. The secret is that "rubbing" surfaces has to be smooth like a glass to prevent premature wear. As for greasing parts, there's actually no requirement and it is not recommended. Rubber and grease or any petroleum products for that matter do not work together very well.

 

[wickware]

Re: Replace just impeller or housing also?

Thanks for the better pics. I?ll still say I do not see what would cause an instant change in water flow vs there are Damages and a need to repair them. All my personal experiences are related to my 1970, 35hp Chrysler in fresh water (vs sharing other?s info that I can relate to from 40 + yrs of Small Combustion and Auto Engines). Good Luck!

 

[jdamron]

Re: Replace just impeller or housing also?

Thanks for the feedback. Yeah maybe the water flow issue is a combination of bad impeller and muffs not on good. I went ahead and ordered the complete kit. I do not want to buy parts that are not needed, but on the other hand while everything is apart I want to do it right. And plus I figure it is still tons less doing this myself as opposed to paying someone so in the long run I figure the full kit is the way to go. I will do another update after the parts get here on if this solved the problem. Thanks again for the suggestions.

 

[jdamron]

Re: Replace just impeller or housing also?

I had not posted an update to this thread because I have not yet been able to really test the work I did yet. But I did end up installing a new impeller with the full kit including hosing, plate, etc. But I have had starting issues since I did this work and I have not really been able to validate the results of the new impeller. However, here are some pictures of the water pump work. Once I get it to start again (subject of a different thread) I will see if the water flow is better. I also changed the oil in the lower unit. I am hoping once I get the engine running that the lower unit will be set for a little while.

 

[jerryjerry05]

Re: Replace just impeller or housing also?

Difference of night and day.
The old impeller was wore and had a permanent set that wouldn't allow proper flex.
It needs to be able to flex back and forth to pick up water.
What's with the running problems?
Start with a compression test.
I've found doing that first can stop a lot of diagnosing?
Then a spark check.

 

[jdamron]

Re: Replace just impeller or housing also?

Difference of night and day.
The old impeller was wore and had a permanent set that wouldn't allow proper flex.
It needs to be able to flex back and forth to pick up water.
What's with the running problems?
Start with a compression test.
I've found doing that first can stop a lot of diagnosing?
Then a spark check.

Yes, I think this will make a big difference. The running problems are detailed in the testing solenoid and where to get replacement thread. I did two separate threads because originally I did not think the work was related and I was working on the lower end while waiting on starter parts. However, the more I think about it these two threads might actually be related. It could be that the bad impeller caused some overheating and that might be the cause of the low compression in cylinder one that I have now which is keeping me from starting.

Thanks.