Tower of Power identification

FFScott6 · Mar 16, 2012

I am considering a Grady White "overnighter 204C" purchase with twins, owner states they are 150hp. I saw them run last weekend. pretty good after 2 yrs. but I know nothing about Mercs. the serial numbers are 5553330 & 5553340 does that sound right? Before i buy this GW I am looking for background info on this inline 6 motor. dependable? repairable (I good at this type of thing), any other "quirks". Fuel mileage or gallons per hour is not a big concern for me since we stay in the upper chesapeake bay and flats.

Thanks in advance - Scott

aussieflash · Mar 16, 2012

Re: Tower of Power identification

What year are these motors?I would start with Compression and Leak down test.

FFScott6 · Mar 17, 2012

Re: Tower of Power identification

I was told 1979 or 80. They appear to have been serviced in the last few years, carbs, tune ups, i noticed bolt heads have missing paint i.e. been removed in the past. PO used it for salt water fishing and fresh water family cruising. other than that that is all I have so far. I want opinions from here before I invest anymore time "looking" at a boat. If the opinions are that these are decent motors and repairable then I'll dig deeper. I'm not afraid to tear down motors and have the proper tools for that. I just don't know anything about these "Towers of Power" mercs.

Thanks for the replies...

Faztbullet · Mar 17, 2012

Re: Tower of Power identification

I going bet those are V-6 motors as they quit making the I-6 150 around serial number range 49xxxxxx and it has head bolts as you stated...

Chris1956 · Mar 17, 2012

Re: Tower of Power identification

Those motors are 115HP if they are inline 6 motors. Likely model year 1979. If they are V6 motors, they could be 150 HP from 1980

FFScott6 · Mar 17, 2012

Re: Tower of Power identification

No they are inline 6cyl for sure. I need some time to figure out how to get my new iphone pics in here. I'm wondering if they are 115's? I found some web pages that kinda make me think that by serial no. I also realize that mercs use less of the model years and more on serial #'s. I have found enough information online, to approximate, what repairs & maintenance it would need. I'll be going back for a second look for "details" of these motors and ask more questions. I meant the heads of many bolts show signs of being removed (scratched and nicked from a wrench), I'm guessing by that it was not neglected. I'll be checking compression, electrical functions, tilt/trim, etc.

Will keep posting here as I get new info. Please keep comments coming.

Faztbullet · Mar 18, 2012

Re: Tower of Power identification

I would be kind of leery on this as the last year they made a stock I-6 150 was 1975 and the 150XS which will have a vented cowling and more of a HO engine was 1978. L lean more toward Chris as they are 115...unless owner is reading cowling wrong . If decal shows 1150 they are 115 and old.

Chris1956 · Mar 19, 2012

Re: Tower of Power identification

Fazt, Last Stock 150HP IL6 was 1977. Distributor model. The 140HP IL6 was made for 1978, 1979 and maybe part of 1980, before being D/C.

FFScott6 · Mar 20, 2012

Re: Tower of Power identification

I'm going for it! 115, 150hp, it'll go faster than I'd really ever use (well maybe once or twice ;-)). I was last in the water mid season 2010, preserved, and not back since P.O. stated job consideration and it's cheaper & less worry going out on a charter.

I did hear it again this past week end, satisfied. they need cleaned up some, I'll also do new fuel lines & filter - tank to motors, plugs, wires, adjust carb floats, clean all the wire connections and coat them, tunes up, decarb, new batteries (ouch 80 buck a pop) basically I'm treating them as a "resurection." port motor needs a reverse lock it's really tight. tilt is slugish so maybe a cylinder & pump rebuild. trim flaps work nicely, Hydraulic steering needs bled but it functions. Most of this is for peice of mind. We're mostly family cruising.

I read somewhere (actually lots) that they are hard astarting but the J/E "fuel primer" is a good fix. Need opinions, please. don't hold back I can take all of your comments. How else will I learn?

Thanks for the input so far - Scott

Chris1956 · Mar 21, 2012

Re: Tower of Power identification

Manual Reverse lock is not used on motors with PTT, as it is unnecesary.

The later model inline motors had enricheners, the early one had choke shutters on two top carbs. Even with the choke shutters, the motors are not hard to start.

Pump up the primer bulb, raise the cold start lever all the way, hold the choke button and crank until she fires. Periodically hit the choke button and feather the cold start lever until she is warm.

FFScott6 · Mar 21, 2012

Re: Tower of Power identification

Thanks for that advice. I should have it home by next w/e. I'll be free to take them apart and learn more. A manual comes with them. His wife found it. Only need a real parts listing and I can get started! I'll also have detail pics tO post.

Thanks again

FFScott6 · Mar 21, 2012

Re: Tower of Power identification

Here is the power end view.

Faztbullet · Mar 21, 2012

Re: Tower of Power identification

The 140HP IL6 was made for 1978, 1979 and maybe part of 1980, before being D/C.

All the 140's even the 1972 model was D/C..

Chris1956 · Mar 22, 2012

Re: Tower of Power identification

Fazt, The 140HP IL6 I was referring to was the renamed 1977 merc 1500, which was listed at 140HP for 1978 and 1979, before being phased out sometime after that.

FFScott6 · Mar 22, 2012

Re: Tower of Power identification

I thought I was onto something

Now you are talking about a 140hp IL6. I confirmed a few minutes ago, I'll be getting the boat & these motors here next Thursday or sat so I'll put up some pictures including a close up of the model & serial #'s on the transom mount. What else or different would help ID these motors? assuming I don't get a manual.

Chris1956 · Mar 23, 2012

Re: Tower of Power identification

The IL6 motors shared a lot of parts, over the years. I think the only way you will be able to figure out what you have is to match the part numbers of the blocks, transfer covers and pistons. The 1977 Merc 1500 and 1978 Merc 140 HP were real similar. They may differ only by cowling paint. The Merc 115HP motors may not have the power pistons, and should have different block and transfer cover part numbers.

That is where I would start....BTW - the 115HP motor were much more popular than the high HP IL6 motors.

FFScott6 · Mar 23, 2012

Re: Tower of Power identification

More good info, thanks. Like I mentioned earlier... speed is good to have, I'm not a fuddy duddy... but I want to know it's there. We are weekend cruisers, make that picnicers. Finding all the neat little coves to hang out. Our AristoCraft with that old 60hp Gale motor just suck the gas. It sure is fun though. Last fall we went from Rouges harbor @v Elk Neck to the Chesapeake Inn & back 10gallons of midgrade & 35minutes each way. We met some nice people though.

I'd like to get them running my way this season and likely tear one down for a rebuild next winter and then the other the following off season. The boat they are on needs elbow grease to shine it up then the 3rd seanon I'll have a real keeper.

Will keep you all updated here as I go. Motor wise. will post in the GradyWhite the other progress.

Scott

mr 88 · Mar 24, 2012

Re: Tower of Power identification

I would not bother rebuilding unless you have low compression,if it ain't broke why fix it? The carbs are a different story and should be torn down. From 1978 when Merc came out with the V6 there HP listings for the L6 were all over the place as they did not want to compete with themselves,then the change in the way they rated HP added to the confusion.Since they made a 150 V6 the 150 L6 became a 140 which turned into a 115 near the end of L6 production.So from 78 on the L6's from 115 to 150 were all pretty much the same motor and within a couple HP of each other regardless of what the HP decal said.The big thing with these great running classics is gas. Unless you up the octane your timing should be retarded a few degrees,gas is not what it used to be.A splash of Stabil gas treatment or Sea Foam keeps the fuel lines etc and carbs in excellent condition.The wiring is prone to rot over time and most people will just splice in new wiring vs buying a new harness,cheaper with the same results.Good luck and do not be afraid to smile as you crack the throttles wide open!!!

FFScott6 · Mar 24, 2012

Re: Tower of Power identification

Thanks MR88. Agreed on the rebuild idea. but for now I'm treating it as a resurection just because he's a freind I never boated with him. better safe than sorry, will be out with family more than fishing buddies. things like fuel lines, carb kits, water seperator (after tank cleaning, tune up... etc, etc. I'm confident he won't sell me down the road. just not taking any chance with kids onboard.

Where is HP measured on these? prop or power head? My old V-4 60hp Gale was measured at the PH been told that mid 50's at the prop.

FFScott6 · Apr 1, 2012

Re: Tower of Power identification

The original idea for this post was to get some additional info... The boat is home not much left on the cowling only the word Mercury. I did verify the serial numbers and the only other numbers I can find, I think mentioned above was on the powerhead just below the middle carb... it is 971-8435. The front "medalion" cover although quite faded does say Thunder bolt ignition. Boy are those covers a bit of a pain... but they do purrrrrr. I can't wait for an in water test... hopefully after Easter.

Thanks for looking

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