Just bought a 1979 140, got some questions.

[Beater]

I just bought a 1979 140 Merc that had not been run in 7 years. It is a very low hour motor and remarkably fired right up. Gas was peeing out the lower float bowl hole but even that quit after a bit of running. I'm going to replace the impellor but is there anything else I need to worry about or should do?<br /> Also is this motor essentially the same size/weight as a 115 of the same year. It looks similar and I was wondering where the extra HP comes from, bigger bore?

 

[Bob La Londe]

Re: Just bought a 1979 140, got some questions.

Sounds like the carb float was stuck. I'ld tear the carb(s) apart and thoroughly clean them. jest, passages etc. No big deal. Get a manual and setting it back up will be easy. <br /><br />The only reason I suggest this, is if the fuel passages are restricted you may be running lean which is hard on a motor, and becaue it runs tank mixed fuel also means it may be operating with inadequate lubrication. <br /><br />Gettting the gasket sets to put the carbs back together will probably take you longer (marginally) than actually doing it.<br /><br />Almost forgot. NEW WATER PUMP. Very very important. Its been sitting. Even though it may seem to have adequate water pressure now that that impeller will deteriorate very very quickly. Replace it. I replace mine every year on all my motors, and if the water pressure starts to drop during the year too.

 

[briannh1234]

Re: Just bought a 1979 140, got some questions.

Once you have it running right, some seafoam will help keep the carbs clean.<br /><br />The 140 vs 115 has been debated and debated. They are actually slightly different blocks. The 140's have a power port in the cylinder bore, while the 115 does not. I don't know if it possible to machine the power port into a 115 block. (It may be a different casting? Maybe is a very expensive machineing operation?) Most everything else is the same except the power ported pistons (A hole in the skirt of the piston that lines up with the power port.) The bore is the same - displacement same, carbs the same except the main jet size...

 

[Beater]

Re: Just bought a 1979 140, got some questions.

Thanks for the info. Reason I asked about similarity to the 115 is that my boat is rated for a 115 but I got a good deal on the 140 and wondered if it would be that big of dif. Obviously weight won't be an issue, I guess I'll just have to go easy on the throttle. Anyone know off hand what one of these bad boys weighs?

 

[dlveleke]

Re: Just bought a 1979 140, got some questions.

If your close enough and looking to sell that 115, let me know.

 

[emckelvy]

Re: Just bought a 1979 140, got some questions.

Your Tower of Power weighs about 300 lbs, give-or-take, depending on if it had Power Trim & Tilt or no.<br /><br />If you have any troubles in the future with the dribbling carbs, probably best to install new floats (they have been upgraded) and new float needle/seat sets. They are not that expensive and are available from the Stealer or aftermarket brands such as Sierra. These guys have pretty good prices on Sierra parts, BTW:<br /><br /> http://www.boatfix.com/searchsierra.asp <br /><br />Carb "packing kits" are available with the commonly-replaced gaskets you'll need if you take the carbs apart. What the dlr calls "carb kit" or "rebuild kit" is VERY $$$ and has a lot of parts that you probably won't need to replace.<br /><br />One thing you can do for your carbs, if they have them, is remove the brass jets on the float bowl covers. There's one jet for each carb and it's visible at the top of the float chamber. If you have this type of carb, the 'back drag' type, it was designed to lean out at midrange & higher speeds for fuel economy, by using 'ported vacuum' to lower the air pressure in the float chamber (thus allowing less fuel thru the carb). <br /><br />With today's gas, you DO NOT want to lean out an Inline! Good way to burn them up. So, taking the 'vent jets' out will make your Tower of Power live longer.<br /><br />As will adjusting the timing to a max of 18 deg BTDC at cranking speed if you have a distributorless motor, or between 18-21 deg BTDC if your motor carries distributor-type ign.<br /><br />Use a major brand of premium fuel. My old 1350 ran happily on regular, but that was about 10 years ago and I expect today's premium probably isn't much better than the regular of days gone by!<br /><br />Don't overprop, death to these motors. Spin 'er up, lightly loaded, to the high end of the rpm range, at WOT. Even though you may not run much at WOT, you can still be overpropped in the midrange and she'll run much better a bit faster. <br /><br />And your Inline will like a good dose of carbon-cleaning solution to keep the rings free. Seafoam, Berryman's B-12, Yamaha Ring-Free, OMC Carbon-Guard, Chevron Techron, all are good cleaners. I like Seafoam myself.<br /><br />HTH and enjoy your Tower of Power.............ed

 

[MortenH]

Re: Just bought a 1979 140, got some questions.

Your 140Hp is rated at the crankshaft, but from the early 80's Mercury started to rate on the propell. Because of that I guess it will be no problem using this on your boat. <br />I don't exactly know how it is on a '79 115, but my '84 115 have power ports in it.<br /><br />-M-

 

[Mercury140-I6]

Re: Just bought a 1979 140, got some questions.

The 79 140 is basically the same as the later 115's. From what I heard, Mercury took the 140 and put 115 cowlings on it, took the 115 and put 90 cowlings on it and discontinued the older 90's.<br /><br />I have a 79 140 also and I had it on a dyno and it is putting out 126hp at the prop.<br /><br />Here is my boat.<br /><br />

<br /><br />I just love to meet people in the same boat as I have with that Force 120, and just blow their doors off with my 26 year old motor. <br /><br />Craig

 

[Beater]

Re: Just bought a 1979 140, got some questions.

Thanks for all the advice guys, hopefully life will get a little less busy and I'll get to work on it! I also have a 1977 Spider that is fun keeping on the road as well to take up my time.<br /> Craig you're right your 140 looks exactly like mine. What length is your Glastron and what HP is it rated for? I'm putting the 140 on a 1984 16 foot Thundercraft and it's rated for 115. I was a bit worried about overpowering but if I change the stickers to 115 that outta do it LOL ! Do you have the same prob I got? I can't lock the motor in the up position cause the power head hits the motor well?

 

[technostingray]

Re: Just bought a 1979 140, got some questions.

How much horsepower can I have and still go to heaven?<br />Ans. The more horsepower you have the quicker you can get to heaven.

 

[Mercury140-I6]

Re: Just bought a 1979 140, got some questions.

Beater:<br /><br />My Glastron is a 16'er, weighs about 1050#'s and is rated for 120 at the prop. I am running a 19 pitch prop and WOT (With just me in the boat) is right at 6,000 RPM's, purrs like a kitten.<br /><br />I have the same problem with the powerhead hitting the motor well (Boat was designed for a V-4), that's why I have the Transom Saver on it. Mine has power trim/tilt, does yours? Without the skipole I can tilt mine further, but still not far enough to use the tilt locks.<br /><br />

<br />Do you have any pictures of yours? Would love to see it<br /><br />Craig<br /><br />P.S. technostupeedo: When I had the 140 powerhead put on the 115 frame, the only reason the mechanic did it was because of the powerhead rating of the motor and the prop rating of the boat, with is the same thing that Beater is doing. When I got it on the water, it would tach 5200 at go well over 65 mph (Too fast for me), that's why I moved down (One prop at a time) to a 19, keeps it around 50 at 6000. I can pull 3 adults on single skis at Sea Level, 2 up here.<br /><br />Craig

 

[technostingray]

Re: Just bought a 1979 140, got some questions.

Thank you for the edification. I don't know whether or not you have been following my journey but your comments would certainly be welcome. I am technically inept and the boat is no picture yet, otherwise I would post a picture.

 

[Beater]

Re: Just bought a 1979 140, got some questions.

Craig<br /> Mine does not have power trim and tilt and I see another post here saying it could be hard on the lower end to use a transom saver without the hydrolic assist. I find that hard to believe though because the use of the transom saver would be negated if you hold the motor up with the hydrolics. I don't have the whole thing together yet but will try to post a pic when I do. I imagine my Thundercraft will weigh more than your Glastron due to the age if not the design. I'm sure I'll have to play around with props much as you did. 65 could indeed be a little too quick but I expect a lot of the Sea Doo boats go quicker with an even shorter hull length.

 

[Mercury140-I6]

Re: Just bought a 1979 140, got some questions.

Beater:<br /><br />I had an old 1250 inline 6 that didn't have power trim/tilt and used a transom saver all the time. The one I used is not the normal one, mine has 4 rubber gromets inside the shaft as a shock obsorber, I use the down trim now to make sure that it is resting on the saver and not on the hydrolics. If the name is still on it, I will post that info tomorrow.<br /><br />As for weight, you might be surprised at how little yours weighs. Yes those mini jet boats and jet ski type vessles are fast, but they really suck down the fuel doing it.<br /><br />A friend of mine got a Bayliner Reflex 14 foot mini jet (Like the Jazz but with a closed bow) He had a Force 3 cylinder 90hp powerhead, and I had the Mercury 6 cylinder 140 hp outboard. He had an 18 gallon fuel tank and I have a 16 gallon fuel tank. We spent a week at Trinity Lake in Northern CA and everytime we went to the gas dock, he put more fuel in his boat than I put in mine. And I was able to walk away from him at any time I felt like it, even while pulling a skier. I did all the pulling of skiers and he just cruised around next to me. I never understood how he could push more fuel through ~70cid than I was pushing through 99cid. Give me a prop anyday <br /><br />Craig

 

[Clams Canino]

Re: Just bought a 1979 140, got some questions.

I've got the same tilt issues with my spashwell.<br /><br />Also, does anyone know where I could get my SS ski-pole extended a bit? The Tower of Power is so tall that while I can use it with skis, I can't run a tube on it as the rope hits the motor. Heh...<br /><br />-W

 

[Mercury140-I6]

Re: Just bought a 1979 140, got some questions.

Clams:<br /><br />My motor was about 4" too tall for the ski pole and they use the same pole for the 16 foot Glastron as they use for the 18 foot, so my solution was to take a 4x4 block of wood, and fibergalss it just before the well for the drain hole under the motorwell, then mount the ski pole onto that. Worked great. The eye/ring at the top of the ski pole is just above the motor.<br /><br />Hope this helps.<br /><br />Craig