rmcderm313
Regular Contributor
Hi Folks,
I need some sage advice... Thanks to a bunch of help from guys on this forum, I've come to a place with my 1987 25HP Merc. where I am about to replace the lower oil seal. The reason I am about to do this is because in order to keep the motor from "coughing" (symptom of a lean fuel condition), I need to turn the idle mixture screw several turns out. The point where the cough goes away, the idle seems very high. Some have speculated and I agree that the lower oil seal may be leaking, thus letting too much air (and I think water too) into the crankshaft, creating the lean condition.
I removed the lower oil seal, which proved to be a bit more difficult than I had planned. It was tough to get out. Here is a before (seal in place) and after (seal removed) shot:
Because I had some difficulty getting this out, I did a small amount of damage to the housing as well as the thin metal piece that covers the end of the crankshaft (what I've come to learn is called the "wear sleeve" as that is the description on the package that I actually received) I have a new lower oil seal as well as a new "wear sleeve kit". The wear sleeve kit that I received looks slightly different from the original part that is on the end of the crankshaft. Through some help on this forum as well as validating the part number I received is the "new" part for this application, I don't really have much choice but to bank on this part being the correct one.
**This "wear sleeve" is labeled as part#7 in the diagram below and identified as "SEAL, CRANKSHAFT - part #43507" on the blowout reference on this parts site, http://www.boats.net/parts/search/M...0/CRANKSHAFT, PISTONS AND FLYWHEEL/parts.html what was actually sent to me was labeled as "WEAR SLEEVE KIT part #822445A 1" which appears to have superseded the original part number.
Here is a picture showing the difference between the two parts. Note the taper at the top of the new one.
Again, through advice on this forum my plan is to "pack" the new oil seal with marine grease, put a light coat of Permatex aviation sealant on the outside rim of the oil seal and tap it into place. My key question here is whether I should make the attempt to replace that wear sleeve. I'm very nervous for two reasons. First, as I mentioned the part looks different. If I remove the existing wear sleeve and then this turns out to be the wrong part I'm kind of screwed. Second, even if it's the correct part, I'm worried about doing damage to the other parts beneath that wear sleeve. As you can see in the photos, there is a black (what looks like) plastic piece inside that wear sleeve. When I look on the parts diagram below, I'm not even sure what part that is. Am I risking damage to that black piece inside? I've lightly tried to pull on that wear sleeve to see if it comes off and it isn't moving easily. If I grab it with vice grips it will probably come off, but at that point, there will be no going back as I'm sure that will destroy the surface.
So I guess I'm looking for any advice here on what to expect or how to approach this. First off, does the surface of that wear sleeve need to be "perfect" for the lower oil seal to do its job correctly? Will minor nicks cause the seal to leak? If so and it is highly advised to replace that wear sleeve, can anyone provide any guidance.
Many have chimed in already with (much appreciated) help on this over the course of a long thread, so I apologize if I'm somewhat repeating my questions here. I'm hoping summarizing the situation might help folks help me make the right choice. I have looked through the SELOC manual and I cannot find this particular procedure outlined anywhere.
As always your help is appreciated,
Rob
I need some sage advice... Thanks to a bunch of help from guys on this forum, I've come to a place with my 1987 25HP Merc. where I am about to replace the lower oil seal. The reason I am about to do this is because in order to keep the motor from "coughing" (symptom of a lean fuel condition), I need to turn the idle mixture screw several turns out. The point where the cough goes away, the idle seems very high. Some have speculated and I agree that the lower oil seal may be leaking, thus letting too much air (and I think water too) into the crankshaft, creating the lean condition.
I removed the lower oil seal, which proved to be a bit more difficult than I had planned. It was tough to get out. Here is a before (seal in place) and after (seal removed) shot:
Because I had some difficulty getting this out, I did a small amount of damage to the housing as well as the thin metal piece that covers the end of the crankshaft (what I've come to learn is called the "wear sleeve" as that is the description on the package that I actually received) I have a new lower oil seal as well as a new "wear sleeve kit". The wear sleeve kit that I received looks slightly different from the original part that is on the end of the crankshaft. Through some help on this forum as well as validating the part number I received is the "new" part for this application, I don't really have much choice but to bank on this part being the correct one.
**This "wear sleeve" is labeled as part#7 in the diagram below and identified as "SEAL, CRANKSHAFT - part #43507" on the blowout reference on this parts site, http://www.boats.net/parts/search/M...0/CRANKSHAFT, PISTONS AND FLYWHEEL/parts.html what was actually sent to me was labeled as "WEAR SLEEVE KIT part #822445A 1" which appears to have superseded the original part number.
Here is a picture showing the difference between the two parts. Note the taper at the top of the new one.
Again, through advice on this forum my plan is to "pack" the new oil seal with marine grease, put a light coat of Permatex aviation sealant on the outside rim of the oil seal and tap it into place. My key question here is whether I should make the attempt to replace that wear sleeve. I'm very nervous for two reasons. First, as I mentioned the part looks different. If I remove the existing wear sleeve and then this turns out to be the wrong part I'm kind of screwed. Second, even if it's the correct part, I'm worried about doing damage to the other parts beneath that wear sleeve. As you can see in the photos, there is a black (what looks like) plastic piece inside that wear sleeve. When I look on the parts diagram below, I'm not even sure what part that is. Am I risking damage to that black piece inside? I've lightly tried to pull on that wear sleeve to see if it comes off and it isn't moving easily. If I grab it with vice grips it will probably come off, but at that point, there will be no going back as I'm sure that will destroy the surface.
So I guess I'm looking for any advice here on what to expect or how to approach this. First off, does the surface of that wear sleeve need to be "perfect" for the lower oil seal to do its job correctly? Will minor nicks cause the seal to leak? If so and it is highly advised to replace that wear sleeve, can anyone provide any guidance.
Many have chimed in already with (much appreciated) help on this over the course of a long thread, so I apologize if I'm somewhat repeating my questions here. I'm hoping summarizing the situation might help folks help me make the right choice. I have looked through the SELOC manual and I cannot find this particular procedure outlined anywhere.
As always your help is appreciated,
Rob
