Contemplating purchase of Mercury 9.9

[cwphoto]

Hi folks:

I've got a older (1985) Mercury 9.8, 2 stroke. She's a real strong runner, but was thinking about upgrading to a 9.9, 4 stroke. I'm wanting a much quieter motor, and really tired of dealing with mixing oil and gas, and hate coming home from the fishing hole smelling like an outboard. A little less noise would be nice too. On the positive side the 9.8 is super easy to work on. I'm also wondering if the 9.9 motor is quiet enough that I could use for trolling, and essentially eliminated a Minn Kota? This would save me a good $500 at least, and also cut down on weight in the boat. I just have a small 1436 Jon, and told I should expect about 20 miles an hour with the 9.9. Does that sound like a realistic figure with one person (200lbs) and boat (350 total weight)?

I'm curious how reliable the 9.9 is, and how hard it is to work on yourself? I am certainly capable of changing and impeller and gear oil, and have even replaced a few fuel pump diaphragms, and can clean carbs, although not one of my favorite jobs. I have an opportunity to pick up a 2012 with about 10 hours on it for $1500. Motor comes with one extra prop and 6 gallon gas tank, so thinking that's a pretty decent price, for my area at least. No maintenance has been done on the motor since purchase, so that is a little concerning, but it runs really well.

So, feedback on this motor please?

Thx,

Troy

 

[Scott Danforth]

the newer 9.8 weighs in at 96# (dry) compared to your 9.8 weighing in at 65#. That alone is adding 31#. from there add the weight of oil and your closer to 40# more. https://www.mercurymarine.com/en/us/engines/outboard/fourstroke/8-99-hp/ keep that in mind when you are thinking of weight. do you get 20mph now with the 9.8? if not, you wont gain any noticeable extra speed. the newer motor is a bit more complicated than the motor you have when it comes to maintenance.

I myself love the smell of 2-stroke, and currently looking for another 82-85 vintage 9.8 shortshaft.

the price appears fair if it comes with an extra prop and fuel tank and indeed does only have 10 hours

 

[Star]

Do not buy the 9.9 mercury! The lower end is poorly designed with needle bearings that take out the case when they fail!!! Tohatsu has a roller bearing like most motors. The motor is made for Mercury by Tohatsu. I have had my used Mercury 05 since 08 and I am happy with it in every way. I does have some minor vibration at certain speeds. Fuel consumption is great!!! The Honda is much smoother across the operating band, but costs much more. The lower unit I bought from mercury cost me $1000 and when it leaked oil Mercury would not fix it!!!! I took it apart to find that they had sheared the o-ring on the bearing carrier when the unit was assembled. I hope this helps you decide.

 

[Scott Danforth]

every merc 40hp and below is a Tohatsu. Just like every other brand. the only difference between the Merc and Tohatsu is the tilt lock and stickers

 

[Star]

Not true Admiral, The 05 has a 3/4' needle bearing on the bottom of the main drive shaft that takes out the case when it fails!!!! There are many other minor differences also.

 

[cwphoto]

Hello Scott:

I think the link you sent was for the pro-kicker, not the standard model. The one I was looking at is stamped at 84 pounds. So essentially 16 pounds heavier. I don't consider that a dealbreaker, particularly if I can eliminate a Minn Kota and a 70 pound battery. I will be way ahead on weight. No one answered whether or not the 9.9 could be used as a troller. The thing is super quiet at idle, so I'm assuming it could. I would never dream of trolling with the two-stroke! Glad you like the smell, but no question they are not as good for the environment. The greatest thing about two-stroke to me is its simplicity, and getting the boat up on plane in about 4 seconds is pretty nice too Not sure how the four stroke would compare here. This is really not a dealbreaker, as these small motors don't consume huge amounts of fuel.

So, what's the consensus on these needle bearings? It seems like there is conflicting information here. While I know the four strokes are more complicated, I guess the question really becomes what additional maintenance, if any, is required? I don't consider having to change oil every 100 hours a major problem, and this last season I don't think I put more than about 60 hours on the boat, so that's one change of oil per season. I'm in Alaska, so we have a 3 month boating season. I would probably pull the carb off of this after purchase and give it a good clean. It doesn't sound like this particular person was using something like sta-bil, so it's quite possible the carb could be gummed or getting there. Lower unit oil is no problem, and a few spark plugs takes a few minutes. Am I likely to have any issues with valves or camshaft? I can't imagine valves need to be adjusted very frequently. What other maintenance issues am I looking at?

And, could someone answer this can be used as a trolling motor? it seems like they are used this way on bigger boats, but also have a different pitch prop, so not sure if it's an apples to apples comparison. I know there's some plates you can get to put behind the prop to slow things down, although I've never use one.

Thanks for all the replies. The seller is holding the motor until Friday for me, so have a few days to decide here.

Troy

 

[Star]

It will run down to around 2.2 mph with a 9 x 9 factory prop on a medium light 14' aluminum. It is a bit fast to me, but my smallmouths are kind of lazy. Top end is about 19mph. I also have a ap55 Minn kota that I would not trade for the world.
I fish in quiet waters so I really like the total quiet. I frequently troll with a pair of loons and the autopilot is wonderful. Your money is not worth anything anyway and you can find some good deals, but get a bow mount with AP or IP. The money you save on gas will pay for it!

 

[cwphoto]

Thanks for the reply Star! I know I had a Torqeedo for a brief while, and nothing beats an electric for quiet running. I suspect with one of those trolling plates you put behind the prop you could slow things down even further, and can't imagine the motor consumes that much fuel at idle, but do appreciate what you're saying. For the small amount of time I am in the lake, the four stroke may still be a good option. I will have to think about this some more.

Now if somebody can just answer the question about the needle bearings, I'll be all set. I certainly don't want to be throwing a $1000 out for a lower unit, so would like to know just how common this problem is you spoke about is. It seems like every brand of motor has a lemon or two. I would think of this problem was widespread I would've heard more about it in all of the YouTube videos I watched. I'm probably more likely to destroy a lower unit by hitting a rock, so plan on investing in a rock hopper or River Runner prop guard.

Troy

 

[Star]

Look at the parts diagram of both motors. It is just bad design and if it fails it takes out the lower case. Also mercury doesn't support their small motors, and some parts are NLA on a 05 motor. Their dealers don't seem knowledgeable, or can't be bothered to work on them! I know that that is a good deal, but in the long run you need support, and I believe that Tohatsu is better at that. I now buy Tohatsu parts because I can't get them from Mercury.

 

[cwphoto]

Well, I took the plunge and decided to purchase this other motor. Interesting to see my two-stroke and four stroke side-by-side. Despite only a 15 pound difference between motors, the four stroke seems huge!. I can certainly appreciate why people like the two strokes. Very compact design, and a real powerhouse for its size. I'm sure I will appreciate the quietness of the four stroke. As to support, the local Mercury dealer here bends over backwards to help me. Parts for example, for this 85 two-stroke are pretty hard to come by, and he can get me most of what I need within about four days. He's more than happy to discuss problems over the phone, etc. I'm sorry you're having such difficulty, but I think a lot of service has to do with the local rep as well. I'm guessing these parts are all coming from the same place ultimately, so it really gets down to how much the individual dealer wants to spend with you. I'm sure they make a lot more money on bigger motors. Although, the 9.9 is pretty popular as a kicker.

Anyway, tomorrow I'm going to run some fuel stabilizer through the engine, and changed out the lower unit oil. There is virtually no discoloration in the upper crankcase oil, so the 10 hour run time seems to be accurate. This engine looks brand-new. I sure did not like the way the transom was flexing on the drive home, and think I'm going to look into some kind of a transom saver to support the engine when I hit bumps in the road, so it doesn't put so much strain on the transom. Anyone have suggestions?

Temperatures are now down to about 40 degrees here, so just going to go about winterizing this. Would sure love to take it out on the water about now! Looks like it's going to be a blast!

Also wanted to ask if anyone knows where I can find an inexpensive service manual? Looks like Mercury wants something like $75, ouch! Is there a PDF version available?

Best,

Troy

 

[tlh 178]

i have a 2003 9.9 4 stroke and love it. i can troll all day at 1mph and up. look on ebay for service manual on a cd rom disk. think i payed 10.00 bucks for mine.

 

[Star]

Tlh 178 what kind of boat is it on?

 

[cwphoto]

tlh 178, thanks for the response I will check up on eBay. One other question I have for people who own this motor. This one came with one of the Atwood 6 gallon tanks, and believe it has a self venting lid. I do not see any screw in vent screw. I know some people experience problems with the self venting gas tanks, and not sure if this motor has issues with them or not. I need to scale down to a 3 gallon for my boat, and may go with another brand other than Atwood if this is an issue. I too would like to know the size of your boat as one mile-per-hour sounds like you might have a slightly heavier boat, although these motors do idle at what, 800 RPMs?

 

[Star]

That motor will suck the sides of your tank in 3" and still keep running. It has a very good fuel pump. with a three + gallon tank I have a range of about 25 miles.
It is a very nice motor if you take care of lower unit oil!!! The carb will also give you grief if you leave gas in it. The idle circuit clogs up and is a pain to clean out.
the motor can be idled down to around 850 in gear.

 

[tlh 178]

cwphoto, i can't help with your fuel tank. mine runs off 20 gal tank. star i have it on my 17ft lund, 135 opti and 9.9 kicker.

 

[cwphoto]

Thank you Star: I just changed out the lower oil this evening with some royal purple synthetic. Based on the look of the oil, I doubt this thing even has 10 hours on it. Looks like brand-new oil, still amber in color. One thing that is a little concerning is the fast idle choke. The linkage appears to be working fine, but I can notice no difference in engine speed. Nada, zip. A few times during slow idle it seemed to want to die, (did not), but if I recall correctly there's two separate jets. One for idle and another for when running at higher RPMs. I'm not sure where I read that exactly or if this is correct, but recall something to that effect. Need to get my hands on a service manual, but they apparently stopped at 2004, at least with the vendors selling them on eBay. Hate to spend $75 on a manual if I don't have to.

As to the tank, it appears the 6 gallon will fit in my boat after all. Very unique shape that allows it to fit quite nicely actually. This does have a screw in vent, which I did not noticed the first time, so think I'm all set there. Would like to get this fast idle choke resolved. I think it took about seven or eight pulls to get this started, and that was after pumping the bulb until it was hard, along with the the primer. If anything maybe I flooded it? It sure seemed difficult to start. My two-stroke starts on the first to second pull, even if I drain it completely of gas.

Something tells me I'm having a fuel delivery problem, and or issue with the fast idle choke. I'm sure compression and spark is fine, Spark plugs look perfect in terms of color. I doubt previous owner used Sta-bil, so may have to pull the carb and clean. Suggestions before I start ripping into this? I actually suspected this would happen due to lack of use, and improper storage.

 

[tlh 178]

pick up a gal of berryman chem dip and soak that carb overnite. make sure you don't soak any plastic or rubber. it takes about 5 mins to pull the carb off. i think you are on the right track. pick up a oem carb kit while you have it apart.

 

[cwphoto]

I was thinking about trying the B-12 Chemtool in a concentrated form, like one bottle to a gallon. I think it normally makes something like 20 gallons. I'm sure the engine would run like crap while it's going through, as is not as explosive as gasoline, but would eliminate having to disassemble the carb as well. There's quite a few plastic parts on the carburetor linkage, and also lots of small O-rings for that matter made out of rubber on the carb. If I was to start getting into dis-assembly, I think I would probably just go to a traditional carburetor cleaner. At this point I would have to do this indoors, as we just had snow this morning. Gotta love Alaska! I'm ready for boating season again! It will probably warm up to above freezing today, so could try some of the B-12 in the driveway during a "warm" period After this, motor is going into hibernation for the winter.

Think I'm going to call the Marine dealer today about the fast idle/choke, as I think this is more than a traditional "choke", and want to make sure there's nothing mechanical going on that I'm missing. If there's anyone that knows more about how this works, please let me know.

Many thanks!

Troy

 

[Star]

I agree about the Berrymans Carb soak from walmart.. around $18.00. Seafoam is my preference as an additive. Be sure to check with your Mercury Dealer about the Royal Synthetic, I don't think he will like it! I have an 05 15hp, so I don't know exactly what kind of carb is on that. I do not have a fast idle/choke on mine. If you could take some pictures of the motor and carb it would help. I think the 08 engine is a smaller displacement block than mine by a bit. Where in Alaska are you?
I was in King Samon back in 1968!

 

[cwphoto]

Hello Star: I'm located in the middle of the state, Fairbanks. Royal purple is now showing up at some of the major chain Auto Suppliers as an alternative to mobile one. We get some of the harshest conditions in the world here, and I would not consider a petroleum-based lube in my automobile. It's 5W-30 synthetic. When you're trying to start a vehicle down to -40 degree, that's when you really appreciate a synthetic. Synthetics will not turn into molasses or break-down like a petroleum-based product.

I will sometimes go to petroleum-based in the summertime, but never in extreme conditions. In my mind, if the synthetics will hold up under the extreme conditions then they will certainly hold up under normal conditions. Bear in mind that our water temperatures during the summer are not much above 40 degrees, different world than lower 48. You go overboard in the water here, and you can quite literally die in a matter of minutes due to hypothermia, and second due to the huge amount of glacial silt in the water. It gets into your clothing, and starts to pull you underwater fast. I always flush the outboard with fresh water when Anyway here's a few pictures if they will attach properly.

Best, Troy