1971 1150 vs 1350

[ro919]

What is the difference parts wise between the two? How can you turn a 115hp to a 135?

 

[Scaaty]

Re: 1971 1150 vs 1350

What is the difference parts wise between the two? How can you turn a 115hp to a 135?

My Merc Guru just built me a 135 from a 115 block for my little Flatbottom rocket..
The build info..
The powerhead I am building for you was originally a '72 1150.
The '72 1150 is a choked down 1350 with a few flow restrictions to give the lower HP rating so Merc wouldn't have to come up with a different powerhead to fill that HP range for the consumer market.
Initially this 1150 needed a rebuild because the inner water jacket had cracked and let water into #3 which was trying to die when I rescued the beast. It still had 95 psi on #3, but the rings had started to seize and consequently had scored the bore.
I had #3 bored .015 and installed a new piston there.
I had all holes pro-honed while I was at it and mic'd for roundness, etc to insure the beast was still within factory tolerences.
The block surfaces were machined too to insure everything was flat in the water jacket areas for a correct sealing.
All other pistons were carefully inspected, mic'd, & cleaned. I replaced one standard size piston too, but (4) of the (6) original pistons went back into their original holes.
Everybody got brand new rings & needle bearings.
The crankshaft got new main bearings.
The end caps got new seals & so did the crankcase.
I installed 1500 reed blocks and reeds, which meausre out the same as the original 1350 reeds.
I am installing '72 1400 carburetors - which are virtually identical to the original 1350 carbs & I am installing the original .0785main jets (we decided on .080 instead..no bog..work great) required for the 1350 at sea level.

The exhaust tuner plate and inner water jacket are both NOS 1350 parts that I had machined to insure they too are flat so they will seal correctly.

These modifications: Main jets, reed blocks, tuner & inner wj complete the conversion of the 1150 to a true 1350.
The only difference between the 1350 and the 1400 blocks is the 1350 had an oval tuner to the mid-section and the 1400 had the dual square port tuner to the mid-section. And,...The inner wj & tuner plate configuration changed barely.
T

 

[Riddc19]

Re: 1971 1150 vs 1350

Wow, that's impressive, how much did this rebuild cost and in the long run do you feel is was worth it to add 20 hp?
Thanks,

 

[Scaaty]

Re: 1971 1150 vs 1350

$2000 for a fresh motor with a lot of new parts (harness, pumps, etc... box/cables, T+T/pump)
Too much work for trying for another 20hp though

 

[emckelvy]

Re: 1971 1150 vs 1350

1150 carbs have larger venturi's in the carb throats; if you change those to the same size (smaller diameter) plastic venturi's used on later motors, and re-jet to 1350 (or 1400) specs, you've got a set of carbs that'll work on the modd'd 1150.

The diff on the reeds is that the 1150 reed stops are only .0741" while 1350's had .1562" stops.

Late 70's 900's, 1150's, 1400's, and 1500's all had .1620" stops so those would be Ultra Trick to use in a modd'd 1150.

Both 1150 and 1350 have Monstrous ports and really wail on the top end. My old 1350 was Very Scary on a 16' Sidewinder. But loads of fun too!

Definitely a worthwhile mod if you're looking for an extra meaure of performance while retaining that classic Red Stripe motor!

Cheers.........ed

 

[Scaaty]

Re: 1971 1150 vs 1350

do you feel is was worth it to add 20 hp?
Thanks,

Darn sure worth it for me...wind resistance from hair has been eliminated...next is drop 50 pounds off the pilot!

 

[gidds]

Re: 1971 1150 vs 1350

Scaaty,

I have to ask one thing..........how fast will that sumofabich go??????

WOW......

 

[Scaaty]

Re: 1971 1150 vs 1350

Scaaty,

I have to ask one thing..........how fast will that sumofabich go??????

WOW......

Well, 12x24 pitched 2Blade SS Hubless (on it now)...15.9 Flatbottom with little weight, 1 inch drop on the chines, center pad 10 inches...
Still breaking it in, but a good punch has the so called Jetskis running in fear...speedo quits somewhere past 50..who knows...all I DO know is I slapped a wake that snuck up on me last Sat...went out somewhere about 5'11..came back about 5'8...
My back says I MIGHT get to go out again in a week..meanwhile, the 25 footer was actually painful today at 1200 RPM...but the dog had fun!
Anyway, darn thing cavitates to about 4000 r's on a full punch, starts grabbing water, then takes off quicker than... hmmm...can't think of a comparision ..a freaking grin! I need to hang a vid cam off my head...ITS THE SOUND! what insulation? wish I had my old louvered XS 150 wrap for it...think I'll be drilling holes over the winter (and put valve springs under the seat bolts!) Damn, I hurt!
Couple more pix (I can slid through a no wake zone at speed..dude taking the pix said about 2 inch wake..! first pic aint speed..just a punch in the 40 mph range with a 13x19 SS prop..(way too little pitch..but hole shot like a top fueler!)

 

[new_boater]

Re: 1971 1150 vs 1350




i just bought a 72 slickcraft ss190 with a 115 merc i hope it does the go fast

 

[Scaaty]

Re: 1971 1150 vs 1350

Prop it right..I settled on a SS hubless 12/24 cupped..any Alum 13 Dia any pitch over 19 works, but like tossing out a chute when ya back off..then bow steer...no prob, just have to be aware..

 

[71'Thunderbolt]

Re: 1971 1150 vs 1350

omg thats awesome... i wish my boat was that small... i bet it would fly as fast as yours.. i have a 18ft ...... it goes though..... i have the 1350 on it.. i saw you mentioned that the #3 cylinder went bad... i have that exact same problem... no compression at all... u said something about the water jacket cracking..??????

 

[croSSed]

Re: 1971 1150 vs 1350

Darn sure worth it for me...wind resistance from hair has been eliminated...next is drop 50 pounds off the pilot!

Scaaty -
VERY nice. Here's mine. I have an '87 115; basically the same thing as a '77 1500 with slight de-tuning; probably makes the same hp as yours. I gps'd this with a 22P Laser II at just under 57 mph. Where do you boat? It would be fun to see how fast we each are...

TG

 

[AMD Rules]

Re: 1971 1150 vs 1350

CroSSed, what rpm is your 22p spinning at WOT? Your boat is similar in shape and size to mine. Running a jack plate, or low water pickup?

Just curious.

 

[Scaaty]

Re: 1971 1150 vs 1350

Well ..been in the big barge of mine all day, and the Pizza is ready..this is a bump..more tomorrow on this..

 

[Scaaty]

Re: 1971 1150 vs 1350

Scaaty -
VERY nice. Here's mine. I have an '87 115; basically the same thing as a '77 1500 with slight de-tuning; probably makes the same hp as yours. I gps'd this with a 22P Laser II at just under 57 mph. Where do you boat? It would be fun to see how fast we each are...

TG

South Puget Sound...I mostly hang around the bay in front of the dogpatch. I'd probably say speed about the same..maybe 60..I gotta get a GPS

 

[Scaaty]

Re: 1971 1150 vs 1350

omg thats awesome... i wish my boat was that small... i bet it would fly as fast as yours.. i have a 18ft ...... it goes though..... i have the 1350 on it.. i saw you mentioned that the #3 cylinder went bad... i have that exact same problem... no compression at all... u said something about the water jacket cracking..??????

If you have zero compression on 3, look at the plug. If ya see a coating of tiny silver balls..ya torched a piston. If ya did, look in the hole at TDC and see what the piston looks like. They (don't know the year of yours) went to I think 78 an offset trigger window to better match the crank, and no more than 21 degrees timing, and run midgrade gas

 

[croSSed]

Re: 1971 1150 vs 1350

CroSSed, what rpm is your 22p spinning at WOT? Your boat is similar in shape and size to mine. Running a jack plate, or low water pickup?

Just curious.

The rpm at absolute top speed is about 5500-5600. No jack plate or LWP. A jack plate is in my future though. Don't know if the LWP will be necessary. I've been getting mixed messages from various places about LWP's. Some say, "yes, use one along with a 24-26p chopper for best top speed" others, "no need for LWP; plug the top few holes on the water pick-ups on both sides, make sure you have at least 10 lbs of water pressure, and use a 23p Trophy Plus" So, I don't know what to do. For sure I will get the jack plate. At that point I'll play around with it using the props I have on hand.

TG

 

[Scaaty]

Re: 1971 1150 vs 1350

The rpm at absolute top speed is about 5500-5600. No jack plate or LWP. A jack plate is in my future though. Don't know if the LWP will be necessary. I've been getting mixed messages from various places about LWP's. Some say, "yes, use one along with a 24-26p chopper for best top speed" others, "no need for LWP; plug the top few holes on the water pick-ups on both sides, make sure you have at least 10 lbs of water pressure, and use a 23p Trophy Plus" So, I don't know what to do. For sure I will get the jack plate. At that point I'll play around with it using the props I have on hand.

TG

Not sure what your hull looks like (like in a Vee with a good pad), but if you are in the 5500-5600 rpm range, I would leave it alone and use it. Yeah, you could go the rear set/jack plate route and a bigger pitch, but then holeshot aint the same, and well, lot of expense involved for a few more mph.
Now, if ya want to fly, get an old XS150 (has LWP gearcase)..set up for much higher rpms', and then a big 2 blade 28-30p will have ya REALLY cookin..my Merc Guru has one, but wants $3500. Others can be found.

 

[OldMercsRule]

Re: 1971 1150 vs 1350

Wish I still had me ol' 14' Carlson tunnel hull flat bottom with me 1250 short shaft, (now dead). The Carlson, (sold it God help me), was rated fer an 85 hp motor, 'fore I took the ol' tag off. Never did GPS the ol' girl but it ran mid 70s MPH on an itty bitty chop, (perfect fer tunnels) next to the ol' 520 floatin' bridge accordin' to a feller drivin his Bemer that paced me. I was grabbin' way to many RPMs fer the ol' 1250 on that run which had a tendancy, (so I was told) ta spit rods from time ta time. I had a hole shot that reminded ya of a GTO! Glad it never flipped when me PT would stick! JR

 

[Scaaty]

Re: 1971 1150 vs 1350

ta spit rods from time ta time
Thats the problem with pushing anything but an XS, which didn't mind 6200