'71 Mercury 650 65hp Outboard

[DrgnRebrn]

I am wondering if anyone can offer me some advice related to this engine. I have started the engine & it fired right up, ran well, and seems to be in overall good condition. After running it though, there was some oil that leaked out from the propeller area onto the ground, nothing significant, but it was there nonetheless. So, I have a few questions.

My first question is, is this something I should be concerned about? I believe this is a 2-stroke engine, which confuses me even more that there seems to be oil leaking out of it, since 2-strokes get their oil from the gas/oil mix. This is where some advice would be helpful, as I know nothing about boat engines.

My second question is regarding the first-time run prep. How should I treat this engine prior to it's first serious run under my ownership? The previous owner admitted that the boat has sat since fall '08 and that the engine hadn't been fired until the day that he posted the ad for it. I'm thinking a total fluids change-out - especially if it really does require oil in addition to the typical 2-stroke fuel mixture.

My third question is regarding the propeller. There is some damage to the blades and I'm assuming this will have a drastic impact on not only the engine's performance on the water, but also the fuel economy. I'm not expecting miracles in a fuel-sipping engine, but I would think that a fully intact propeller blade would increase the efficiency of the engine by pushing more water with less effort.

My fourth and final question (for this post at least) is related to long-term care & maintenance. I've never owned a boat before, but I've heard a lot about winterization. While we are just now getting out of the long winter here in Utah, and this question is getting a little ahead of myself, I'm the type of guy who likes to know what he's dealing with & what he needs to do up front. If there's any post-run maintenance I need to do after having it out on the lake, I'd like to know now. Also, do I need to "winterize" this engine? I have heard from some people that outboard engines do not need to be winterized the same way that I/Os do.

That's it, I'd really appreciate any feedback & advice you may have. Now here's some pics!

I paid $300 for the boat, trailer, & engine - off an ad that read "65 hp Mercury outboard engine-RUNS GREAT-comes with free boat & trailer!" Thanks again!

Here's the link to the thread for my '66 Glastron Futura V-150 boat restoration:
http://forums.iboats.com/showthread.php?t=385991

 

[achris]

Re: '71 Mercury 650 65hp Outboard

So many questions, so little time.... But here goes..

I am wondering if anyone can offer me some advice related to this engine. I have started the engine & it fired right up, ran well, and seems to be in overall good condition. After running it though, there was some oil that leaked out from the propeller area onto the ground, nothing significant, but it was there nonetheless. So, I have a few questions.

My first question is, is this something I should be concerned about? I believe this is a 2-stroke engine, which confuses me even more that there seems to be oil leaking out of it, since 2-strokes get their oil from the gas/oil mix. This is where some advice would be helpful, as I know nothing about boat engines.

Quite correct, the oil is mixed with the petrol and is 'ingested' by the engine for lubrication of the crankshaft bearings and cylinder walls (and a few other things). That fuel (complete with oil) is drawn into the combustion chamber and burnt. If however, you have a cheap crappy oil that doesn't burn completely, then you end up with a thick, black, sticky mess running down the inside of the exhaust chamber in the driveshaft housing.... Then it comes out the gearbox, like you're seeing.

My second question is regarding the first-time run prep. How should I treat this engine prior to it's first serious run under my ownership? The previous owner admitted that the boat has sat since fall '08 and that the engine hadn't been fired until the day that he posted the ad for it. I'm thinking a total fluids change-out - especially if it really does require oil in addition to the typical 2-stroke fuel mixture.

Been sitting for 2 1/2 years.... It DEFINITELY needs a new water pump impeller (the one that pumps cooling water up from the lake and around the engine to stop it overheating. I'd also change the lower unit/gearbox oil, and spark plugs, and clean out the fuel system. 2 stroke fuel goes off quite quickly, and when it does it rots the inside of everything it touches.

My third question is regarding the propeller. There is some damage to the blades and I'm assuming this will have a drastic impact on not only the engine's performance on the water, but also the fuel economy. I'm not expecting miracles in a fuel-sipping engine, but I would think that a fully intact propeller blade would increase the efficiency of the engine by pushing more water with less effort.

That prop needs replacing/repairing.

My fourth and final question (for this post at least) is related to long-term care & maintenance. I've never owned a boat before, but I've heard a lot about winterization. While we are just now getting out of the long winter here in Utah, and this question is getting a little ahead of myself, I'm the type of guy who likes to know what he's dealing with & what he needs to do up front. If there's any post-run maintenance I need to do after having it out on the lake, I'd like to know now. Also, do I need to "winterize" this engine? I have heard from some people that outboard engines do not need to be winterized the same way that I/Os do.

See below for winterization of an outboard. (from the Merc manual)

That's it, I'd really appreciate any feedback & advice you may have. Now here's some pics!
I paid $300 for the boat, trailer, & engine - off an ad that read "65 hp Mercury outboard engine-RUNS GREAT-comes with free boat & trailer!" Thanks again!

Here's the link to the thread for my '66 Glastron Futura V-150 boat restoration:
http://forums.iboats.com/showthread.php?t=385991

 

[DrgnRebrn]

Re: '71 Mercury 650 65hp Outboard

Excellent, thank you achris! Do I need to look for a specific prop that fits my engine, or are they somewhat universal? Is the 2-stroke fuel mixture 50/50, and what type of oil should I be using to avoid this from happening again (weight, brand, type, etc)? After I drain the oil from the gearbox, what type should I replace it with? Finally, with this being an older engine, do I need to look for a specialized water pump, and if so, how do I determine what kind?

Sorry for the onslaught of questions, but I really appreciate the advice!

 

[Huron Angler]

Re: '71 Mercury 650 65hp Outboard

I have a '71 Merc 800 and it requires 50:1 fuel/oil mix.

You most likely will want to order a service manual for the outboard if you plan on doing all the maint yourself. Should be a good motor if it was well cared for and you keep up on service.

I'll have to check out your glastron resto too

 

[Huron Angler]

Re: '71 Mercury 650 65hp Outboard

http://www.iboats.com/Mercury-Water-Pump-Repair-Kits/dm/*******.255702507--**********.356019159--view_id.271499

This is a link to water pump kits for your OB from iboats.

You should replace the lower unit oil with new, also available at iboats.

 

[Moody Blue]

Re: '71 Mercury 650 65hp Outboard

Excellent, thank you achris! Do I need to look for a specific prop that fits my engine, or are they somewhat universal? Is the 2-stroke fuel mixture 50/50, and what type of oil should I be using to avoid this from happening again (weight, brand, type, etc)? After I drain the oil from the gearbox, what type should I replace it with? Finally, with this being an older engine, do I need to look for a specialized water pump, and if so, how do I determine what kind?

Sorry for the onslaught of questions, but I really appreciate the advice!

Props are usually specific to a mfr, ie., Merc, OMC, Yamaha etc. There are three specs that are important to match to your motor/boat. They are # of splines on the prop shaft (yours are probably 15), the overall diameter of the prop and lastly, the pitch, or how far the prop would travel in one revolution (theoretical).

If you look on the back face of your prop around the center hub there should be a series of numbers. The last few digits will describe your pitch, ie., 17P means 17" pitch. The numbers may also be stamped somewhere on the body of the prop.

50:1 (50 parts gas, 1 part oil) is the correct mixture. Use any name brand MARINE 2 cycle oil rated TC-W2 or W3.

Again, lower unit oil is MARINE grade SAE 90 extreme pressure (EP) gear oil. Lots of posts here describing how to do it.

Water pump is a vane type impeller that is driven by the driveshaft inside the waterpump housing. You need to replace at least the impeller with the correct one for your motor. Size of the impeller changes with different models and HP. If in poor condition, you may need to also replace the upper pump housing and other seals. No way of knowing until you get it apart.

 

[DrgnRebrn]

Re: '71 Mercury 650 65hp Outboard

Thanks MoodyBlue & HuronAngler! I am trying to figure out which water pump kit is for my engine, but I'm having a hard time finding a serial number anywhere on the engine. Do I need to take the cap off to find this? Also, I guess my engine is a 2 cyl, but I was told by the seller that it was a 4 cyl. To somewhat substantiate what he told me, there is a 4 on the engine housing. Not sure what that means, but if you could share some expertise regarding this it'd be greatly appreciated

 

[Huron Angler]

Re: '71 Mercury 650 65hp Outboard

The serial # should be on the motor in between the transom clamps. It's usually greasy and dirty so it may need to be wiped down to make out the numbers.

I believe it's on other parts as well but I haven't dismantled mine yet.

 

[Moody Blue]

Re: '71 Mercury 650 65hp Outboard

Your motor is a 4 cylinder, 2 cycle motor.

Look on the top of the tilt/steering tube between the two transom clamps for the S/N plate. Should be riveted on. The S/N will be 7 digits, something like 2886514. Judging from the coloring on the motor shrouds I would guess your motor is between a 1969 and 1972 model year.

 

[Aqualift]

Re: '71 Mercury 650 65hp Outboard

 

[Wingedwheel]

Re: '71 Mercury 650 65hp Outboard

I have a '73 850 and its very close to yours. If you do have oil leaking out from around the prop-shaft its possibly the inner and outer seals which are located behind the thrust washer on your prop shaft. Seeing the damage to the prop I hope the shaft didn't get bent when the previous owner hit whatever it was that caused the damage. These two seals are about $12 apiece and if you know what your doing you can change them without pulling the carrier housing. If your a novice I recommend paying your local marine service dealer the 2-3 hours they will charge you to replace them. They can also check the shaft when they have it out.

 

[bayoulee]

Re: '71 Mercury 650 65hp Outboard

That looks nearly identical to the one I'm working on and the reason I got on here! If that prop was run long enough with that chunk out of the blade, it throws the thing out of balance which can cause wobble in the shaft and make the bearings go out and could cause the seals to leak. Good luck with it- I will be posting more on my motor as well, which may eventually be helpful to you and vice versa.

 

[egclassic]

Re: '71 Mercury 650 65hp Outboard

I too have a 73' 850 and have been working on it all winter. Be sure to check all of the wiring on your motor, I had to replace the internal harness ($110) on mine due to corrosion, apparently common to these older merc's. Also, be careful around that distributor, no longer available to buy.

 

[road.ripper]

Re: '71 Mercury 650 65hp Outboard

DrgnRebrn

if you look up my older posts you may find some good info on your engine and what to fix .. my best suggestion is buy a MERCURY manual dont bother with the cheaper ones they have most of the info but it gets confusing looking for YOUR engine details amidst all the models cheap books cover. As Achris will atest to i have the same engine as most of you in here and i have been workig on it all winter .
mine is a 1970 650 4cyl.
good luck

road

 

[DrgnRebrn]

Re: '71 Mercury 650 65hp Outboard

Wow, thanks for all the advice everyone! This place is great! I hope I'm not getting into something too extensive. I have worked on car engines before, older and newer. I have even helped my dad & brother rebuild a couple of them, but I've never touched or even seen a boat engine. I know that they should be somewhat similar, but I also know that they are most likely very different in several ways. I wouldn't be surprised if the seals down by the prop are bad. Just the fact that the engine sat for 1 1/2 years without having been run could dry out seals and cause leaking to occur. The strange thing is though that it only leaks when the engine is on, is that significant?

egclassic - Thanks for the FYI. I am planning on doing a full tune-up & that will include inspecting the wiring & connection points.

Wingedwheel - I'm going to go ahead & get a Mercury manual & take a shot at taking the prop apart & replacing anything that needs to be replaced. I think that I could get her figured out with a good manual, which brings up the question - where do I find one for this year engine? Are they hard to come by, or is it something like Chilton's manuals for car engines where you can still easily find them for older engines?

Aqualift - Thanks for the pics on locating the serial number, those are very helpful!

Moody Blue - Thanks for the clarification on the 4 cyl vs 2 cyl question!

bayoulee - I'll be sure to check out your thread, as well as keep mine updated with as many pics and, hopefully, vids documenting my progress.

I hope I covered everyone who's responded so far. I really can't thank you each enough for the advice. This site truly is a great resource. I'm a total newbie with boats, but I already feel like I am gaining a sense and familiarity with the language, care, & pride in owning & working on them.

 

[DrgnRebrn]

Re: '71 Mercury 650 65hp Outboard

Props are usually specific to a mfr, ie., Merc, OMC, Yamaha etc. There are three specs that are important to match to your motor/boat. They are # of splines on the prop shaft (yours are probably 15), the overall diameter of the prop and lastly, the pitch, or how far the prop would travel in one revolution (theoretical).

If you look on the back face of your prop around the center hub there should be a series of numbers. The last few digits will describe your pitch, ie., 17P means 17" pitch. The numbers may also be stamped somewhere on the body of the prop.

Moody Blue - Do I have to remove any parts from the lower unit to gain access to the numbers you're referring to? I looked in the center of the prop on the back end, and the only numbers I could see were "153", nothing else. Of course, there may be some grime hiding other information, but that's the best I could do tonight. If needed, I'll remove the center nut & see if I can't find some additional numbers beneath it, or clean up the grime a bit & see if that uncovers any mysteries.

Question - If my seals are bad on the lower unit, should I replace them before using the boat this season, or will I be ok with waiting until late fall/winter?

 

[achris]

Re: '71 Mercury 650 65hp Outboard

...Question - If my seals are bad on the lower unit, should I replace them before using the boat this season, or will I be ok with waiting until late fall/winter?

Is the oil really black, thick and sticky, or is it more like gearbox oil?

Black and sticky is 2 stroke oil.

If you suspect gear oil, then drain the gearbox and refill it. Look at the old gear oil to see if it has water in it... (After an engine's been sitting for a while I would do that anyway, at the very least).

Chris.......

 

[DrgnRebrn]

Re: '71 Mercury 650 65hp Outboard

The oil is dark black & thick, but I suspect gear oil rather than 2-stroke oil because it doesn't smell like gasoline.

I will drain the gear oil tonight & look for water. If there's water present in the gear oil, then I'm assuming that is an indicator that I need to replace the seals prior to taking her out on the lake?

If this suspect liquid is 2-stroke oil, then what? Should I consider that to be normal, for that "sludge" to slowly leak out of the exhaust occasionally? Is there any way to remove the sludge from my engine prior to first-use? Also, what is the safest way to run my engine off of the lake? I've heard of someone using a 5 gal bucket full of water & placing the prop in it.....don't know if that will work or not...maybe I could connect a hose at a water intake point for the water pump? I've seen a flushing tool at my local store that looks like it has 2 rubber suction cups on each end of a "safety pin type" spring, one of the "suctions cups" having a hose fitting on it. Should I purchase that & connect my hose to it in order to run my engine?

 

[DrgnRebrn]

Re: '71 Mercury 650 65hp Outboard

Another question - I am trying to narrow down an affordable propeller, but when I use iboats propeller search tool for outboard engines I am only finding props for a 65hp 2 cyl engine....mine is a 4 cyl....is this something that I should be concerned with, or does it not matter so long as I get the correct pitch, diameter & spline count?

 

[Moody Blue]

Re: '71 Mercury 650 65hp Outboard

Yes you need to remove the prop to read the info.

The oil you are seeing sounds like unburnt combustion products. Gear oil is not dark and smells really bad.

The proper way to run the motor out of the water is on a pair of muffs. They connect to a garden hose and clamp onto the lower unit over the water intake ports.

As for the prop, try and get some numbers off the old one first to get an idea of where to start. What size is your boat? Length, width and approx weight if you have it. I wouldn't think it matters whether your motor is a 2 cyl or 4 cyl. They both produce the same HP.