Question about Force 40 lower unit seal and screen.

[32251]

http://www.boats.net/parts/search/M...E000001 THRU 0E093699/GEAR HOUSING/parts.html

If you click on the link you will go to a parts diagram. I was working on the water pump/impeller on my Force 40--1994 model. Everything was fine till I drained the oil from the lower unit to change it. It looks like coffee with cream. There must be some water getting into the lower unit. Look at part number 36 on the diagram pt# F40307-2 is a seal that goes under the water pump plate. Made of rubber with a tiny spring around the opening where the drive shaft goes through.

Is there a way to replace that seal without taking the lower unit apart. I think I can dig the seal out with an ice pick with no problem, but can the replacement just be slid down over the shaft and pushed in with marginal effort?


Also take a look at part number 34....a screen #819228. What I found when I took the unit apart is just a piece of plastic with really no screen on it. This part is NLA. Do I HAVE to have it in there?? I don't even really know how it was fitted in the unit. It was kind of lying in there.

Thanks for your help!!

 

[roscoe]

Re: Question about Force 40 lower unit seal and screen.

Yes you can replace the seal without a tear down. But what about the other seals? which one is leaking?

 

[32251]

Re: Question about Force 40 lower unit seal and screen.

Yes you can replace the seal without a tear down. But what about the other seals? which one is leaking?

Thank you Roscoe! How would you remove the seal if you were doing it?
I had thought about taking some aluminum flashing and wrapping some around the drive shaft to protect it where it goes through the rubber on the seal and then drilling a few holes in the seal to give access to some kind of pointed tool to pry up the seal....yes/no?

Also here is a pic of the seal and the replacement. I think the seal is installed backwards. There is a tiny spring that wraps around the rubber on the seal to pull it tight against the shaft. The manual says spring side up....maybe I have it reversed...I can't see why it won't work either way.

As for installing it, if I could find a length of pipe that would fit over the shaft and make contact with the seal edge, it could be tapped in, or if I did not have a full length of pipe then a couple of partial lengths would work using the bottom piece to fess up against the seal and an upper piece as a slide hammer. What do you think.

 

[32251]

Re: Question about Force 40 lower unit seal and screen.

Roscoe, while I have your ear, take a look at the seal on the top of the pump housing. The seal in it now is an all rubber seal, easy to pop out. The replacement seal is metal on the out side and is tough to get lined up to go in. The top edge of the metal seal is VERY thin and sharp and also tapered. Would it be better to flip the seal over and install from the flat bottom side. That would give a large surface area to press against. Manual says spring side up, but both of these seals, the original AND the replacement have no little spring around the rubber. Advice please.

 

[32251]

Re: Question about Force 40 lower unit seal and screen.

. But what about the other seals? which one is leaking?

As for which seal is leaking, these are the only two seals I have access to. I would say that the bottom seal under the plate is more suspect as I can move the shaft just a bit side to side and see water seeping between the rubber and the shaft. I slid the new seal over the shaft and can tell that there is much better "grab" between the rubber and the shaft on the new seal.

If there are other seals in the prop section.....I don't have the tools or the advernturous attitude to go there...yet. Thank you for sharing your expertise.

 

[32251]

Re: Question about Force 40 lower unit seal and screen.

Also in regards to the screen piece. I found where it goes, but it is providing no screening action as the original perforated plastic sides have disintegrated and are now fully open, so there is no screen action at all. Should I address this or just leave it be.

 

[roscoe]

Re: Question about Force 40 lower unit seal and screen.

As for removing the old seal, you can rip it out with whatever means you have as long as you don't chew up the driveshaft.

Put the new seals in the way they are supposed to be, don't flip them over.

There are seals on the prop shaft.

Also seal gaskets on the fill and vent screws, that should be replaced with new every time you change the lube.

I guess I wouldn't mess with the screen situation.

 

[32251]

Re: Question about Force 40 lower unit seal and screen.

Roscoe. I got both of the seals in. The seal under the pump took some time but I got it out and the new one in. I wish that I could have replaced the shaft bearing that is under the bottom seal. Parts lists say it is NLA. There is a little bit of play in the shaft as it goes through that bearing, but I don't know what is too much and what is acceptable.

I put in a new thermostat and am headed to find some new washers for the drain plugs as the bottom one is cracked up. Hopefully this will at least cut down considerably on water getting into the lower unit. This engine had the original thermostat in it. There are tool marks on the drain plugs so maybe the lube was change as it should be. The impeller had some torn spots on it. I am going to fire it up this afternoon and see if this stops the overheating.

 

[32251]

Re: Question about Force 40 lower unit seal and screen.

Tested the motor in a big barrell of water...NO OVERHEATING!!!!! New impeller and thermostat did the trick. That thing was spitting all kinds of water out the back! Hopefully the new seals will keep the water out of the lower end.

I want to thank all the folks on this forum for all the info here. If a hack shadetree with a box of tools and a manual can do this then anyone here can.

Next system I will rebuild on the 40hp Force is the carb. The electrical will be later on since the motor seems to running pretty good. Could be much better at idle.

Cold start was hard, but I think my battery is a little low.