Three Topics on Maintenance of 2001 Mercury 90-HP Two-cycle

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Author Topic:   Three Topics on Maintenance of 2001 Mercury 90-HP Two-cycle

jtms posted 02-19-2012 08:43 PM ET (US)
I have a 2001 Mercury 90-HP two-cycle Saltwater outboard. I looked in my manual and didn't see a model number for the correct fuel-water separator. Which one should I run with this engine? I have been running a 10-micron, but not sure if I should get the short or long filter from Sierra to use.
On another note, I changed the lower unit oil yesterday and curious to see what the used oil should look like. It was dark green as it should be, but there was a small amount of the lighter green chalkier looking fluid in the oil. Hopefully it isn't water, but wanted to check and get some other opinions.
Lastly, anyone have a good recommendation for grease for lubricating the steering rod and other parts as required in the manual. I used lithium grease, but it doesn't seem to be very thick.
Thanks as always-

jtms posted 02-19-2012 09:16 PM ET (US)
I think I might have done a dumb dumb. I didn't realize you had to replace the gaskets for the drain screws after every use. This would explain if I do in fact have water in the lower unit.
However, would still like to hear feedback on fuel water separator and grease. Thanks
kwik_wurk posted 02-19-2012 10:39 PM ET (US)
If you are talking about the small (film canister small) in-line fuel filter element on/in the engine, that is not a separator, that is simply a filter.
As for an external filter, I use a racor 120R-RAC-01, a 10 micron. (Has a rating of 30gpm, so plenty big.)
Dooh...got to use new seals on the lower unit glugs. I buy them en-mass, because several of my engines use the same size. (works out to $0.15 a piece, have a 5 year supply)
Re-using the gasket can be done in short notice, but I have observed once they crush and get wet, the seal will split in two rings when you unscrew them. (Making them useless.)
Chocolate milk fluid of any kind indicates water mixing. Get new seals on, then see if this stops the amount of 'milky' next time you go out. (I suggest you put a small jar to collect some drippings when you re-seal the screws, then compare later.)
You need to get marine grade grease, holds up in salt water.
And if you do not have a SS steering rod, make sure you keep up on it. (I can't remember what year or if your has a SS rod.)
L H G posted 02-19-2012 11:48 PM ET (US)
[Changed topic to begin a general discussion of fuel-water separating filters. This thread already is covering three topics. I do not want to expand it to include a fourth topic, on the general need for a fuel-water separating filter. If another discussion is desired on that topic, please start a new thread. This one will have to be content with just three topics.--jimh]
Boston Whaler does not factory rig boats that use on-deck tanks with water separating filters.
pcrussell50 posted 02-20-2012 04:01 AM ET (US)
[Asked for further discussion about the use of fuel-water separating filters. Please start a new thread for that topic. This fellow wants to install one, and is just looking for a recommended product. See you in the new thread you will start if you want to continue the new topic. Otherwise, let's let this thread just have its three original topics--jimh]
jimh posted 02-20-2012 09:56 AM ET (US)
I doubt there is only one correct fuel-water separating filter for use on a 2001 Mercury 90-HP two-cycle engine. Select any fuel-water separating filter with a fuel flow rate that is appropriate for your engine. A 90-HP engine won't be consuming more than about 10-gallon/hour. Almost any filter will be able to handle that flow rate. For more advice about fuel-water separating filters, see
http://continuouswave.com/whaler/reference/fuelFilter.pdf
from the REFERENCE section listing of articles about Fuel Systems.
See your owner's manual for the procedure for changing the gear case lubricant. Gear case lubricant which has been contaminated with water will appear as a creamy color emulsion.
Any good marine grease can be used as a lubricant on an outboard. I am sure your owner's manual recommends a Mercury marine grease, probably their 2-4-C grease. However, read the owner's manual. Often there are a few locations where a specific lubricant is required. It is best to follow those recommendations.
jtms posted 02-20-2012 10:32 AM ET (US)
Thanks for the responses. I wanted to ensure that I didn't need a "specific size" fuel water separator for a smaller 90 hp engine. When I say "specific size" I mean the actual size or volume of fuel that a filter will hold. I know Sierra makes a long 10 micron and a short 10 micron. Sounds like it really doesn't matter which one so I will continue with the larger because it will allow more water to be trapped.
I always go to the manual before posting any question, but my particular manual is very sparse with information. I suspect the newer engines have more detailed manuals.
Thanks again-
jimh posted 02-20-2012 09:31 PM ET (US)
According to my old Mercury mechanic, a common problem they see on outboard engine gear case oil drain screws which have been serviced by the owner is the use of either two seal washers or no seal washers. The original seal washer is often stuck in the drain hole surface and has to be pried out or scraped out. Many people don't notice this; they think there was no seal washer and install a second one. Or, do-it-yourself-ers omit the seal entirely. It is best to use a new seal and very carefully remove the old seal. Do not damage the seat of the seal in the drain hole when you remove the old seal.
Also, use a very large flat blade screwdriver if your engine has the old-fashioned slotted screw head on the drain plug. The more modern drain plugs come with a hex insert which works much better. That is what Evinrude uses. If you have a slotted drain plug, be careful not to bugger-up the slot by using a screwdriver blade that is too small.
For more advice on routine seasonal chores, see
http://continuouswave.com/whaler/reference/winterizeOMC.html
Step 6 of the procedure describes how to change the gear case lubricant.
jimh posted 02-20-2012 09:37 PM ET (US)
A good way to get some advice on routine chores is to become acquainted with your local dealer. Go to the dealer. Buy all the stuff you will need from the dealer. Yes, it will cost $5 more than if you drove across town to WALMART. While there ask for some advice about what you need and how to do it. Don't ask "the kid." Don't as the teenaged girl at the register, the one with the body piercing and tattoos. Ask one of the old guys in the shop. Go around 1 p.m. when they are coming out from the back to eat lunch. Hold up an armful of products and say, "Is this what I need to change the oil in the gear case?" Or something like that. Most of the time the mechanic will help you pick the right stuff off the shelf, and you can get some advice on how to do it while you are talking to him.

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Author	Topic: Three Topics on Maintenance of 2001 Mercury 90-HP Two-cycle
jtms	posted 02-19-2012 08:43 PM ET (US) I have a 2001 Mercury 90-HP two-cycle Saltwater outboard. I looked in my manual and didn't see a model number for the correct fuel-water separator. Which one should I run with this engine? I have been running a 10-micron, but not sure if I should get the short or long filter from Sierra to use. On another note, I changed the lower unit oil yesterday and curious to see what the used oil should look like. It was dark green as it should be, but there was a small amount of the lighter green chalkier looking fluid in the oil. Hopefully it isn't water, but wanted to check and get some other opinions. Lastly, anyone have a good recommendation for grease for lubricating the steering rod and other parts as required in the manual. I used lithium grease, but it doesn't seem to be very thick. Thanks as always-
jtms	posted 02-19-2012 09:16 PM ET (US) I think I might have done a dumb dumb. I didn't realize you had to replace the gaskets for the drain screws after every use. This would explain if I do in fact have water in the lower unit. However, would still like to hear feedback on fuel water separator and grease. Thanks
kwik_wurk	posted 02-19-2012 10:39 PM ET (US) If you are talking about the small (film canister small) in-line fuel filter element on/in the engine, that is not a separator, that is simply a filter. As for an external filter, I use a racor 120R-RAC-01, a 10 micron. (Has a rating of 30gpm, so plenty big.) Dooh...got to use new seals on the lower unit glugs. I buy them en-mass, because several of my engines use the same size. (works out to $0.15 a piece, have a 5 year supply) Re-using the gasket can be done in short notice, but I have observed once they crush and get wet, the seal will split in two rings when you unscrew them. (Making them useless.) Chocolate milk fluid of any kind indicates water mixing. Get new seals on, then see if this stops the amount of 'milky' next time you go out. (I suggest you put a small jar to collect some drippings when you re-seal the screws, then compare later.) You need to get marine grade grease, holds up in salt water. And if you do not have a SS steering rod, make sure you keep up on it. (I can't remember what year or if your has a SS rod.)
L H G	posted 02-19-2012 11:48 PM ET (US) [Changed topic to begin a general discussion of fuel-water separating filters. This thread already is covering three topics. I do not want to expand it to include a fourth topic, on the general need for a fuel-water separating filter. If another discussion is desired on that topic, please start a new thread. This one will have to be content with just three topics.--jimh] Boston Whaler does not factory rig boats that use on-deck tanks with water separating filters.
pcrussell50	posted 02-20-2012 04:01 AM ET (US) [Asked for further discussion about the use of fuel-water separating filters. Please start a new thread for that topic. This fellow wants to install one, and is just looking for a recommended product. See you in the new thread you will start if you want to continue the new topic. Otherwise, let's let this thread just have its three original topics--jimh]
jimh	posted 02-20-2012 09:56 AM ET (US) I doubt there is only one correct fuel-water separating filter for use on a 2001 Mercury 90-HP two-cycle engine. Select any fuel-water separating filter with a fuel flow rate that is appropriate for your engine. A 90-HP engine won't be consuming more than about 10-gallon/hour. Almost any filter will be able to handle that flow rate. For more advice about fuel-water separating filters, see http://continuouswave.com/whaler/reference/fuelFilter.pdf from the REFERENCE section listing of articles about Fuel Systems. See your owner's manual for the procedure for changing the gear case lubricant. Gear case lubricant which has been contaminated with water will appear as a creamy color emulsion. Any good marine grease can be used as a lubricant on an outboard. I am sure your owner's manual recommends a Mercury marine grease, probably their 2-4-C grease. However, read the owner's manual. Often there are a few locations where a specific lubricant is required. It is best to follow those recommendations.
jtms	posted 02-20-2012 10:32 AM ET (US) Thanks for the responses. I wanted to ensure that I didn't need a "specific size" fuel water separator for a smaller 90 hp engine. When I say "specific size" I mean the actual size or volume of fuel that a filter will hold. I know Sierra makes a long 10 micron and a short 10 micron. Sounds like it really doesn't matter which one so I will continue with the larger because it will allow more water to be trapped. I always go to the manual before posting any question, but my particular manual is very sparse with information. I suspect the newer engines have more detailed manuals. Thanks again-
jimh	posted 02-20-2012 09:31 PM ET (US) According to my old Mercury mechanic, a common problem they see on outboard engine gear case oil drain screws which have been serviced by the owner is the use of either two seal washers or no seal washers. The original seal washer is often stuck in the drain hole surface and has to be pried out or scraped out. Many people don't notice this; they think there was no seal washer and install a second one. Or, do-it-yourself-ers omit the seal entirely. It is best to use a new seal and very carefully remove the old seal. Do not damage the seat of the seal in the drain hole when you remove the old seal. Also, use a very large flat blade screwdriver if your engine has the old-fashioned slotted screw head on the drain plug. The more modern drain plugs come with a hex insert which works much better. That is what Evinrude uses. If you have a slotted drain plug, be careful not to bugger-up the slot by using a screwdriver blade that is too small. For more advice on routine seasonal chores, see http://continuouswave.com/whaler/reference/winterizeOMC.html Step 6 of the procedure describes how to change the gear case lubricant.
jimh	posted 02-20-2012 09:37 PM ET (US) A good way to get some advice on routine chores is to become acquainted with your local dealer. Go to the dealer. Buy all the stuff you will need from the dealer. Yes, it will cost $5 more than if you drove across town to WALMART. While there ask for some advice about what you need and how to do it. Don't ask "the kid." Don't as the teenaged girl at the register, the one with the body piercing and tattoos. Ask one of the old guys in the shop. Go around 1 p.m. when they are coming out from the back to eat lunch. Hold up an armful of products and say, "Is this what I need to change the oil in the gear case?" Or something like that. Most of the time the mechanic will help you pick the right stuff off the shelf, and you can get some advice on how to do it while you are talking to him.