lower unit lube change...novice needs advice

[metalmessiah]

just bought my first boat last week.took it out twice last weekend & it ran great.want to change the lower unit fluid without trashing anything.<br />the motor is a 1997 Force 120 on a 17 foot Astro bass boat.got it to top out at 56mph.wondering about the correct procedure for doing this.where is the drain plug?there are 2 plugs marked <br />check & fill but I dont know where the drain is.also there is a small hole about 8" below the check & fill plugs that seems to drain some muddy <br />looking stuff when I trailer the boat after an outing.should I be concerned?it seems to grind a little when shifting into gear if I dont hold the button<br />in until it is fully engaged but if I hold it all the way in until I have fully engaged forward or reverse it seems to engage a little hard but doesnt grind.<br />thanks for any help you guys can give.

 

[OBJ]

Re: lower unit lube change...novice needs advice

Hi Ya' metal.<br /><br />Changing the lower unit oil is no big thing. I will take for granted that the two screw (check & fill) are clearly marked. Put a pan or something to catch the old oil under the lower unit and remove the screw marked fill. Then remove the screw marked check. The fill screw will drain out the old oil and the check screw is the vent. Once the oil is drained out, refill the lower unit from the bottom up. Fill until the oil comes out the top hole. Once it does, replace the top screw and tighten. Then, be quick, remove the fill hose or bottle and replace the bottom screw. Bingo. Yer done. It's also a good idea to let the engine set verticle for about 15 minutes or so before draining. This will let any nasties like water or anything else to settle to the bottom of the lower unit. When you first crack the lower plug, take it out just enough to see whats' coming out first. Look at the oil and note any large pieces of metal or a large amount of water. If it comes out all oil, great. Your good to go.

 

[OBJ]

Re: lower unit lube change...novice needs advice

Let me go back for a sec. Just remembered that these motors sometimes had a fill plug at the top of the lower unit. The drain plug will be at the bottom of the lower unit, close to the skeg. This is where you drain the old oil out. The fill and check plug, the check plug may be labeled "vent" will be on the upper portion of the unit. After draining, replace the drain plug and add oil in the fill hole until it comes out the check or vent hole. Checking the oil still applies. Sorry about the goround. Just didn't want to confuse you.........not to much anyways.

 

[metalmessiah]

Re: lower unit lube change...novice needs advice

yes, the check and fill plugs are on the upper portion.no need to bleed the air or anything after I fill it back up?are the brands sold at wal-mart ok to use?

 

[OBJ]

Re: lower unit lube change...novice needs advice

No need to bleed. The lower unit will vent as you fill. What I unually do is fill slowly turning the prop as I do. This will make sure the lower unit is filled. Honestly about the type of oil to use, I would go with a name brand like Merc, Bombardier, Yamaha, etc. I don't know much about the brands K-Mart uses but I, in my own opinion, would rather spend a couple extra dollars for a proven brand name. Again, this is just my own opinion.

 

[metalmessiah]

Re: lower unit lube change...novice needs advice

thanks for the tips....one last question, I am going to have to order it online if I go name brand as all the shops are closed when I get off work....how much will it hold?

 

[CBU]

Re: lower unit lube change...novice needs advice

metalmessiah:If this reply isnt already posted many folks here will advise to look for presence of h2o when loosening the lower drain plug-if water drains then gear-oil look for sealing trbls(search other posts-much good info here).If no water also well advised to replace sealing washers/gaskets for fill/vent plugs-these are easy to find/inexpensive+often source of h2o engress.Clymer manual say gearcase capicity is 22.5 oz-oil sold in 1qt. bottles.

 

[OBJ]

Re: lower unit lube change...novice needs advice

Easy way to go is get a quart and get a pump for quart bottles. These pumps generally fit any quart bottles and makes the change out of oil easy. Double check CBU's post also. Replacing he plug washers is a good idea. Cheap to.

 

[metalmessiah]

Re: lower unit lube change...novice needs advice

ok, now Im confused....why do I need a pump for the bottle if the fill plug is on the upper portion?

 

[NathanY]

Re: lower unit lube change...novice needs advice

You fill it through the bottom hole until it comes out of the top hole.

 

[OBJ]

Re: lower unit lube change...novice needs advice

Metal, it's just an easy way to fill. Call me lazy but the tubes with the pointed ends suck. Especially if yer' filling from the bottom up as most lower units do. Yours fills from the top down and then up. You can go with the tubes but they are clumsy. Try a pump.

 

[G DANE]

Re: lower unit lube change...novice needs advice

metalmessiah<br /><br />Congratulatings I think you bought a great boat with a good working motor - fast too !!<br /><br />One thing more. About your shifting :<br /><br />Shift into gear with authority. These have no slippery clutch like a car, and engaging very carefull only allowes the metal surfaces to shave each-other. Do not force but do it natural rapidly. If it stays in gear performing like you told, usually no problems at all !! If you notice small metal particles in first part of used oil it will probably be from shifting too carefully - if you have an owners manual, there should be a small note about shifting.

 

[roscoe]

Re: lower unit lube change...novice needs advice

OutboardJim is correct. On this motor the bottom hole is for draining. The top hole toward the boat is the fill hole, the hole just behind it is the vent or overflow hole.<br /><br />Your lower unit holds 22.5 ounces of lube. Lots of the guys here use the WalMart branded lube, as do I.