Getting ready for Spring

[Jimmy_Blue]

I have 1990 90 Hp Force and I'm getting it ready for spring and was wondering if there's anything else I should do besides what I'm gonna list here. I changed my lower unit oil, checked/cleaned my spark plugs. Cleaned my fuel pump filter and I'm gonna do all the lubing that's listed in my maintenance manual. I was thinking of adding a telltale also. If I missed anything please let me know. The previous owner had it winterized but no telling how far they went cause they didn't change the lower unit oil so needless to say I won't be having them do any of my maintenance lol. Thanks in advanced if you respond.

 

[Frank Acampora]

Re: Getting ready for Spring

If you have recently bought the engine, spend the 20 bucks and replace the water pump impeller. Spend another 4 or 5 and replace the fuel pump diaphragm and gasket. Even if the old one is still good, you will absolutely know that the replacements are good.

 

[Jimmy_Blue]

Re: Getting ready for Spring

I wish I would of looked here before I went to the parts store cause I just got back. Now to do the impeller that would involve me draining and taking the lower unit off? After I replace the diaphram will I need to do any adjustments or anything? I seen one of your other posts frank that said if your gonna buy a manual the better one's are clymers so that's what I bought.

 

[Frank Acampora]

Re: Getting ready for Spring

Obviously you must drop the lower unit to change the impeller, but it has nothing to do with the gearcase so your fresh oil is ok and will not need to be drained.

Changing the fuel pump diaphragm is really simple--six screws to remove and pop the cover. It is sitting right there on the side of the engine tucked under the electronics mounting board. The screws may take a bit of force to remove. You will need a narrower screwdriver to get the center two screws. Just remember that it will probably tear the gasket so buy one of them too.

 

[Jimmy_Blue]

Re: Getting ready for Spring

Hey Frank does 50 ft lbs of torque sound right for the prop nut cause that's what my maintenance manual say's for standard torque for the size of nut I have? It didn't specify my Year of engine so I just went to the standard table. It didn't take that much force to come off so I just wanted to make sure.

 

[Jimmy_Blue]

Re: Getting ready for Spring

One last question for ya frank. That step by step impeller change instructions you typed up will apply to mine for the most part also?

 

[Frank Acampora]

Re: Getting ready for Spring

50 foot pounds may be standard torque for that size nut BUT personally, I feel it is way too much for a prop. You should use a self locking (Nylock) nut and just run it down snug enough so it will not back off. The only thing it is doing is (in combination with the washer), keeping the prop from coming off in reverse.

Remember: The prop is located by the thrusr washer and the nut is not joining two pieces under load so it does not really need to be torqued up---UNLESS it is a non self-locking nut which needs the 50 ft-lbs to keep it tight.
If your prop uses the Mercury tabbed washer to positively secure the nut, a half a grunt should be tight enough, then bend a tab or two down to lock it.

Your 90 has a dual exhaust lower which basically unbolts the same way but you probably have a speedometer tube running out the lower unit which needs to be disconnected-- Not sure exactly when Merc did this. The water pump is plastic Mercury on studs--a little different but not radically so. Also, the drive shaft is two pieces with a joining collar at the pump and there is at least on different seal on the top of the pump casing. Once you look at it though it will be easy.

 

[Frank Acampora]

Re: Getting ready for Spring

You made me so curious about the prop nut that I went out and tested mine just now. I don't usually torque my nuts (no pun intended) so I usually give them about 1/2 grunt (Uh!) force. Turns out that 1/2 of my grunt works out to about 8-10 foot pounds on three of my engines.

By the way: The grunt is a valid unit of measurement: 1/2 grunt is snug, 1 grunt is tight, 2 grunts is very tight and a triple grunt (Uh, uh, UHH!) will sometimes strip screws. --And if you are really lucky, bark your knuckles in the bargain. So you can see that the triple grunt is reserved for the most severe duty cases.

 

[Jimmy_Blue]

Re: Getting ready for Spring

Thanks for the laugh cause that was funny. Mine doesn't have any kind of extra locking mechanism besides the self locking nut so I'll probably go ahead and torque it to around 120-150" lbs just to be safe.