Is there any way to add trim to a Merc 1250 SS?

[Propster]

My freind has an old Merc 1250 short shaft and he wants to add a tilt/trim, a jackplate and dual cable steering. It is going on a little Carlson Challenger, so he can't add much setback. Is it possible to retrofit just the trim from a later 115 or 150? If that will not work, will a later mid fit an earlier powerhead and lower?

[Raceman]

To answer the second part of your question, the mids will not interchange. The bolt pattern is different at the base of the powerhead and the exhaust isn't close to lining up.

As Wogi pointed out, all the trim stuff will work and the tilt/trim parts are all the same for both long and short engines.

[Techno]

Isn't this a detuned larger engine?
I seem to remember the large dog of a set was built in several HP models by carb changes, more restrictive tuners and some porting differences. Except for the porting would the carbs and tuner make any difference?

[Raceman]

Techno, the 1250 was actually the biggest engine in it's series.....the last of the old crossflows. The 1250 ended in 69. Although the 1150/1350 in 70 & 71 had the same bolt pattern and would bolt on the 1250 mid, they had the new direct charge port layout and corresponding piston deflector shape. Although I never had a chance at direct comparison, I'd guess the 70/71 1150 represented a performance increase over the previous year's 1250, if not in sheer top end numbers, certainly across the RPM range. The only difference between the 1150 and 1350 in 70/71 was reed stops and a replaceable plastic diffuser which somewhat restricted the size of the carb venturi's.

[Raceman]

Wogi, one more comment on your 115/140 statistics: The 72 ONLY 1150 was a direct carryover from the 70/71 engine. The 72 still had the old bolt pattern on the bottom and the small diffuser/low reed stops. The 72 1400's had the newer bolt pattern. This is the only year model that Merc ever had 2 different bolt patterns on inline 6's making them non interchangeable. It's also the only year that the 1150 was ever offered short shaft. This was done because there were remaining parts from the short 1350's of the previous year and at first there was no availability of a short 1400. Merc apparently first said there would be no short 1400's, but released them later in the year. The 4 cyl engine of 72 was also a 71 carryover with the old bolt pattern.

In 73, when everything got back to normal with everything having the newer bolt pattern, the boost port was added and the horsepower rating was bumped to 150. The 1150 no longer had the choked reed stops and the small diffuser. I was told this 73 stop/diffuser statistic by an old Merc employee years ago. The first 1150 I ever went in was a 75, so I don't know it first hand. The 75 1150 did not have the tight stops or fat diffuser, so I do know for sure that it was changed by then. In the 75 1150, the boost port was still not present and I'm not sure when they finally did add it, but it did happen later.

[CrayzKirk]

Probably old news, however...

I believe '84 was the year of the HP rating change when the 140 became the 115 and the 115 became the 90. I have an earlier model 90 powerhead and the exhaust ports are tiny. They look a lot like the earlier 100 and 110hp motors; small and round instead of big and rectangular. I also have a couple 1150/1350 powerheads. If you have to replace the inner water jacket, you buy a complete kit that includes the baffle as well. I think this changes the exhaust pulse timing to be more efficient. The porting on it looks identical to the late model 140/115 with the exception of the boost port. Don't have any 73-83 115hp motors to compare it with though...

Anyway, back to the original question...

According the the service manual, you can add power trim to any post '66 motor since it has the sturdier swivel bracket. All you need are the tilt rams, hoses, pump and wiring harness. If you want to disassemble the motor, you could use a late model integral system since the dynafloat mounting is (I believe) identical. Of course, this involves a lot of work and the other parts are readily available. You also don't have to worry about the serial number plate and titling issues. Some states are really picky about that sort of thing.

Kirk

[Raceman]

Wogi, I only see one problem in the long/short shaft 1150 stats. Merc never sold that extension kit direct from the factory and they never manufactured one for those engines. I think that I remember that they didn't recommend it be used in the later stuff, but I could be mistaken on that. It was made by Bay Machine (can't remember the city but as of a few years ago they were still in biz, may still be) I believe that Bay Machine built the ones for the old white motors and early black ones too, rather than them being a Merc part, but I won't say that with certainty.

I verified that with my friend who who retired from Merc several years ago after working with em almost 20 years, first in warranty, then as a service school instructor. He was actually a Merc Dealer in the early 70's till about 78 when they closed the store and he went ot work for Merc. He says absolutely, positively NO short 1150's after 72 or 1150's with the new bolt pattern ever factory mounted on a short mid.

The stats on the 72 engine came from him. His story was that Merc first said there would be no short 1400's and many racers built the transom up on their tunnels to run a 20" motor. He showed at the races as a spectator with one on some type of high perf V. He was able to get the motor before it was announced because of his father's former employment with Merc and close connection with Carl K.

[Raceman]

I haven't read all the way through that stuff as complex as it is, but I will when I've got more time. I will say that there are countless examples of Merc (and many other manufactureres) throwing up parts list for items that either never made it to production or had substantial changes by the time they do.

As a side note, there's only about 4" difference between a short and a long inline 6. We frequently call em 15 and 20" motors, but 15 and 19 might be more accurate. A std. V6 mounted flat on the transom will have the propshaft almost an inch lower than a longshaft inline mounted in the same location.

As far as my old Merc bud, his father was very involved at Merc when Carl was at the reigns. His father ran the proving grounds at Sarasota for an extended time after he was moved to Fla. from Wisconsin. My friend also worked at Lake X as a teenager, with lots of time as a test driver, along with his brother during this time and when their dad left Merc they all three moved to Savannah Ga and ran a Merc Dealership there. Later, they moved to Mid Ga. and opened and ran another dealership for a ghost owner who had multiple stores. After the local store closed, my friend moved to Atlanta with Merc and worked with them until the late 90's. The first years at Merc he fielded outboard tech questions on the phone, along with several other guys in Atlanta. Later he taught service school there. Through his dad, he got all the good stuff as a kid and rubbed elbows with all the racers of the time. During the years at Merc in Fla and then the dealerships in Ga. he and his brother had an old Glastron and later Allison and finally a pair of Magnum tunnels with countless 1000, 1250, 1400, Twisters, 1500's etc, in addition to having access to the latest toys at Lake X during the time he was there. He's a walking Merc encyclopedia and I've never been able to catch him wrong on a single statistic he's quoted, although I've made a hobby out of trying, based on research, not personal knowledge. I've tried hard to get him to join here and post, but he just isn't interested in playing on his daughter's computer.

[Raceman]

I was never interested in 25" V6's, so I didn't pay attention to them, but I do believe that Merc sold em with spacers in em. I also think the kit was engineered by Merc and probably made in house, as opposed to the inline kit which was made by Bay Machine.

There's no doubt that there were economic preasures on the marine industry in the 70's. It's the very reason that the Merc store here closed, along with several others owned by the same guy, forcing my friends out of a job, and to move out of town since they had no real ties here and no job experience outside of the marine industry.

As far as the short inlines with adapters, I just don't believe they were ever factory installed for any reason. I'm sure a number of dealers did it. At least 3 of the 1500XS's that I have now, as well as the only complete 850XS that I have, had spacers in em when I found em. There's no question that a lot of em were added, especially when engines were swapped to other boats.

I guess we're debating details that don't matter much as far as short 1150's, but when you take the word of a guy who has over 30 years experience with Merc, not only as a dealer, but as a factory warranty adviser, tech rep, and finally service school instructor, it's hard to contradict facts that he says he's certain of.

My OPINION also is that Merc didn't offer the spacer kit for the larger style 4 cyl and late 6 cyl inlines as a quicksilver accessory. I won't say that it's any more than an OPINION based on a foggy memory of something that wasn't all that important to me at the time. I was trying to put a short 1500 on an 18' SuperSidewinder without butchering the transom and I do distinctly remember the dealer giving me Bay Machine's phone number. This would have been in 1974 and it seems like if it had been an availble Merc accessory, he'd have just ordered it.

I don't recon' all this stuff even matters, but it is too damn cold to run the boats and I guess talkin' about em's the next best thing.

[MagicFloat]

Throughout the 1970's,we bought lots of Bay Pattern Works extension kits for short shaft Mercs, from 20hp up to inline 150's. They came with everthing. longer studs, driveshaft and shiftshaft exstenstions,even a reverse lock exstention. But I'm pretty sure Merc never made any back then. Merc made them for later models to make a 25" out of a 20"

[BRENT GILL]

man ya'll wore me out reading all this research .
hang a CMC external unit on there and get about 5" of set back to go with it for about $ 400.00