Mercury 2.0L Crate Power Head Build - 135 vs 150 vs 175 differences?

[Reefsider]

Hi, I have some questions about the differences between models of 2.0L engines. I have worked on a lot of smaller engines (1-3 cyl) but this will be my first v-6 repair/build.

I have a 1987 2.0L Mercury 150 that blew up and wrecked the block. I took it apart and saved what I could and junked the block. The electrics have the 1/2" ply stator (vs 5/8").

I also have a 1979 2.0L Mercury V-175 in pieces that we have had around for years. Most of the wiring is rotten on it but there are still some good parts. The power packs have a different part number; 332-5524A1 (1979 - 175hp) vs 332-7778C (1987 -150hp, 1992 -200hp).

I ended up buying a new 2.0L core power head that someone had sitting around for a while from kijiji to fix it. He didn't remember/know anything about it really. The power head is stamped 12/94 so I'm guessing it's a 1995. It had some interesting differences from my old motor so I wanted to figure out what's going on. After doing a lot of searching, measuring and comparing part numbers I believe I have a 1995ish 2.0L V-135. The head part number is the same and it has the same intake configuration.

I also picked up a blown up 1992 2.4L 200 as the guy pretty much gave it to me lol. Its block has a giant hole in it, it's missing one of the power packs and the trim motor. It is an XL mid section length also, so the mid is no use to me. It had the horizontal intake parts I needed though. I also liked the cowl and thought I might be able to use it and some other common parts if I need them.


Differences I can see so far:

The heads are one piece instead of 2. The part number is 18787-04.

The old intake/reed cages were mounted vertically and the new motor has them horizontal.

The old motor had the coils mounted on the exhaust back plate and the new motor doesn't have the same holes and mounts. New motor only has 4 threaded holes. Also the new exhaust back plate has one less bolt on the bottom of the cover.

Mounting for other electronics like voltage regulator are missing or the holes are there but not threaded. There are other mounting holes but they don't line up to my 150 electrics.


Questions:

What are the differences between the 1987 150, the 1979 175 and the 1995 135 being as they are all 2.0L engines? Is it just the carbs, tuner plate and heads?

When I look at the '95 V-135 parts drawings I noticed that the coils and mounting plate for the 2.4L 200 seem to be the same as the 1995 V-135. Is it ok to just use those in my 150 electrics? The other parts of the electric system are different except the power packs.

I'm not really sure what parts are best to use to build this motor. Can I just figure out new mounting for all the 150 parts and run that system?

I bought CCMS fiberglass reeds for the motor. Do I need to change the jetting to compensate for the extra flow if I don't port and polish the cages or modify the tuner plate?

I was thinking of porting and polishing the reed cages and tuner plate but was recently told not to bother as it robs mid range power. I might shave the heads 30 - 50 thou to make the motor run better. I'm assuming these are de-tuned to bring the 150hp motor down to 135hp?


Parts I have to use:

3 sets of carbs, all look the same but one set is from a 2.0L 150, one from 2.0L 175 and one from a 2.4L 200

2 lower units, one 1.87:1 gear ratio and one 2:1

2 power packs 332-5524A1 (175hp),

3 power packs 332-7778C

Complete electrical system for 1987 2.0L 150

Complete electrical system for 1992 2.4L 200

Some electrics from 175 2.0L.

1987 20" mid section with 3 ram trim that leaks down badly

1992 25" mid section (need 20") with newer style trim that works but is missing the electric motor.

I'm mostly concerned with the electrical and fuel system at this point but I thought I would give the full story so it's all there for better advice and future reference.

Thanks very much for any help,

Reefsider

 

[Dukedog]

not enough "band width" on here ta try n explain differences and what will or won't work.. your spannin' 3 generations of motors.. '76 ta '82, '83 ta '90, '91 ta '99..... hard parts, some will and some won't but you need ta be able ta tell tha difference.. really can't do it ona computer... electrical will if ya keep all 9 amp, 16 amp, 40 amp stuff (stator, rec., reg.,) in their group includin' flywheels.. switch box is a switch box is a switch box.. numbers and price changed thru tha years but all will work on any switch box motor, trigger, coils also... but if one is bad its possible ta destroy a "new" build ina second.. your gamble..

carbs.. you can use tha ones from tha '87 (wh's) but you will need different linkage.. tha '94/'95 has horizontal front half.. linkage from what ya say is a '92 2.4 200 might do it.. it should be horizontal but would need ta see all linkage ta know what it actually is... '91 up are whats known as "fat blocks".. carbs were wmh's so linkage changed... also they didn't build any kinda 2.4 after '91 and it was a XR4 150.. tha 200 was a 2.5.

to do tha "right thing" with your "new" power head, ebay everything pre '91 including tha so called '92 2.4 200 stator, rec/reg.. its worthless.. get tha right parts for tha "fat block".. you don't know what parts are good and whats bad.. its used junk that could destroy tha new motor.....

gear cases: if either has a "pin" stickin' outta tha top of tha drive shaft use it as a spare only...

20" can will bolt to tha 25" clamp and trim but with no motor how do you know tha trim works?.. you will also need '91 or later 2 piece adapter plate for tha '94/'95.. tha '87 adapter plates will work but not recommended to tha novice....

jan: only difference with 135's and 150 2.0 motors are carbs and maybe tuner.........

jmo......

 

[jimmbo]

until 1982 the power heads were crankshaft rated and there was a 150 hp and a 175 hp, both were 2 liter. There was also a 200hp and a 225 hp based on a 2.33 liter block. In 1982, the engines became propshft rated. there were now only 3 engines. a 2 liter 150. and two 2.33 liter engines, a 175hp, and a 200hp. In 1986 a 2 liter 135hp was introduced.

Pre 1983 there was crank rated 150, 175(2 liter), 200, and 225(2.33 liter)
Post 1985 there was prop rated 135, 150(2 liter), 175, and 200(2.33 liter)
See a pattern?

Rumour in the 80s was
crank rated 225 became the prop rated 200
crank rated 200 became the prop rated 175
crank rated 175 became the prop rated 150
crank rated 150 became the prop rated 135


So your 79 175hp MAY be very similar to the 87 150hp when it comes to Porting timing, Exhaust, and Carbs. But there will be, as mentioned, year to year variations in linkages, ignition systems, Choke/cold enrichment, Premix vs. Oil Injection(premixing gas-oil prior to carbs). Location of reeds on block. Changes to oil recirculation lines. Differences to the transom bracket and power trim systems. Differences to charging systems. The list gets really long as the 90s approached

I never went thru the microfiche at the dealership comparing part numbers to find out what the differences/similarities were

 

[Dukedog]

Rumour in the 80s was
crank rated 225 became the prop rated 200
crank rated 200 became the prop rated 175
crank rated 175 became the prop rated 150
crank rated 150 became the prop rated 135

pretty close 'cept for this part.. but like said "its a rumor thats still being debated .......... reed plate/front half, block configuration, port timing, finger ports, head configuration (squish and pockets) all added to changes.......

but he's really jus askin' what can be used ona '94'/'95 block assy..... which will come with experience 'cause part numbers jus won't tell tha "whole story"..........

jus courious.. who calls a 2.4 a 2.33 in public?..

 

[Reefsider]

not enough "band width" on here ta try n explain differences and what will or won't work.. your spannin' 3 generations of motors.. '76 ta '82, '83 ta '90, '91 ta '99..... hard parts, some will and some won't but you need ta be able ta tell tha difference.. really can't do it ona computer... electrical will if ya keep all 9 amp, 16 amp, 40 amp stuff (stator, rec., reg.,) in their group includin' flywheels.. switch box is a switch box is a switch box.. numbers and price changed thru tha years but all will work on any switch box motor, trigger, coils also... but if one is bad its possible ta destroy a "new" build ina second.. your gamble..


Ok, I understand that the system are not entirely compatible as they are different amperage etc. not sure which motor is what amperage but that's easy to figure out if i search for it. You answered one of my big questions; That the power packs and coils are all interchangeable. The triggers as well? I know the flywheel and stator have to match as with the reg/rec.

I'm new to large outboards but I'm confused as to how a faulty electrical system or components like switchboxes can cause an engine to have physical damage? I have worked on lots of motors but they were mostly single or twin cylinder with cdi or nitro motors without electronics. If the pack fails or is faulty the engine just stops working. How is it different with these motors? If the pack is shot wouldn't I know right away? It would either not run or run very badly right?

I'm not really sure what you're suggesting? Are you saying I should go out and buy all New or NOS parts for a fat block and get rid of all my used parts or just buy all the used parts I still need for the fat block on eBay or wherever? I doubt very much I have the money to buy all new parts. If I had that kind of money I probably would have bought a working motor instead of the replacement core lol.

I have a Mercury factory service manual for a 1987 150 2.0L on the way so that will help with some details. I plan to bench test any electronics I can, procedures should be in the factory service manual.

The 200 hp must be a 1991 then. I did look it up by SN but it was a long time ago. I do remember it was a 2.4L. I am not sure the trim works but I know it held well before the guy that sold me the motor stole the pump out of it. He even had the courtesy of telling me he was taking it, saying he would replace it with a new one as he needed one for that day. Wasn't pleased but wasn't there to stop him and so it's gone.

Anyways, I hope to use the clamp, trim and maybe the tuner plate from the 200 and the shorter mid from the 87 150. Also like I said the coils and trim selenoids from the 200 are a perfect match to the "fat block" parts so I'm good there. The lower from the 200 doesn't have the pin in the drive shaft for sure so I'll probably use that lower and change the drive shafts. Unless they don't change over? I want to use the 200 cowl because it's the one piece bucket style as opposed to the clam shell style. The tuner plate on the older motors doesn't have the holes for the cowl mounts. I can drill and tap the older ones but if I can use the 200 tuner plate it would be easier.

I also used the horizontal intake from this motor including the carb linkages. I still have to figure out which carbs were for which motor but they all look the same externally so I should be able to use the 150 carbs, I haven't looked at the choke systems yet but I know the old carbs were different than the rest. The 200 has the oil tank and injection drive as well as all the electronics that might go with that. I don't think the 1987 had that but I'm not sure, I'll look when I'm at that set of parts next. I really don't mind running premix though and just capping that off. I don't trust any of those injection systems anyways.

I have a pretty good parts shop to call but they aren't really mechanics so they are great with cross referencing parts and figuring out what parts should be on certain motors but they have a hard time with figuring out what is compatible although they are happy to call their reps and ask. But I'd like to do as much research as I can myself before that.

Jimmbo:

I completely forgot they changed over the hp ratings. Yes that makes sense that the 175 would be almost the same as the 150 of the different rating system.

I guess the most important thing is the internals of the '95 135. Is there going to be a difference in ports or internal channels from that to the 1987 150 that would prevent me from being able to use the electrical system or the carbs from the 1987? Especially as the '95 is considered a "fat block"? I know the front of the motor is different like the intake and carb setup etc but would that have any effect on what electric system I use? Or only what carbs I use? If it's the carbs, can't I just use the 200 carbs that were on the horizontal intake and re-jet for the 150?

From the parts diagrams between the '95 135 vs '95 150 the only real difference is jetting and the heads. The 135 has 18787 heads and the 150 has 18488 heads. I was planning to shave the heads to compensate. I could be wrong but that's all I've noticed so far. Again this is between 1995 models not the 1987 150, I haven't taken the time to do a full comparison on those yet.

Thanks again for all the help and responses.

Reefsider

 

[Dukedog]

hope tha answers below help ya some...........

Ok, I understand that the system are not entirely compatible as they are different amperage etc. not sure which motor is what amperage but that's easy to figure out if i search for it. You answered one of my big questions; That the power packs and coils are all interchangeable. The triggers as well? I know the flywheel and stator have to match as with the reg/rec.

'79 is a nine, '87 is a 16, '91/'92 is a forty but water cooled and not very good.. merc only used that type for two years then went to tha two air cooled reg/rec.

I'm new to large outboards but I'm confused as to how a faulty electrical system or components like switchboxes can cause an engine to have physical damage? I have worked on lots of motors but they were mostly single or twin cylinder with cdi or nitro motors without electronics. If the pack fails or is faulty the engine just stops working. How is it different with these motors? If the pack is shot wouldn't I know right away? It would either not run or run very badly right?

sw boxes can cross and/or double fire or worse when bad causin' a cyl. ta not know what tha hell is goin' on... a well tuned efi motor will try ta run on one cylinder and will run on two.. jus not very well. lotsa folks can't tell when its runnin' on five other than tha lose of few hundred max rpm.. carb needs at least 4 firin' ta run

I'm not really sure what you're suggesting? Are you saying I should go out and buy all New or NOS parts for a fat block and get rid of all my used parts or just buy all the used parts I still need for the fat block on eBay or wherever? I doubt very much I have the money to buy all new parts. If I had that kind of money I probably would have bought a working motor instead of the replacement core lol.

I have a Mercury factory service manual for a 1987 150 2.0L on the way so that will help,with some details. I plan to bench test any electronics I can, procedures should be in the factory service manual.

this ('87 'lectrics) will work for ya as long as tha parts check out

The 200 hp must be a 1991 then. I did look it up by SN but it was a long time ago. I do remember it was a 2.4L. I am not sure the trim works but I know it held well before the guy that sold me the motor stole the pump out of it. He even had the courtesy of telling me he was taking it, saying he would replace it with a new one as he needed one for that day. Wasn't pleased but wasn't there to stop him and so it's gone.

tha '91 200 is a 2.5 motor.. very first 2.5 200 fat block.. if its a 2.4 then its xr4 150.. only 2.4 fat block made... makes no never mind anyway.. tha chargin' system is junk.. water cooled reg/rec that is way, way over priced if goes south.. merc only used that system 2 yrs.
side note: tha '90/'91 anything is possible comin' from merc.. they had some strange things put together durin' that block change... jus sayin'..........

Anyways, I hope to use the clamp and trim off that with the shorter mid and possibly the tuner plate from the 200. Also like I said the coils and trim selenoids from the 2.4 are a perfect match to the "fat block" parts so I'm good there. The lower from the 200 doesn't have the pin in the drive shaft for sure so I'll probably use that lower and change the drive shafts. Unless they don't change over? I want to use the 200 cowl because it's the one piece bucket style as opposed to the clam shell style. The tuner plate on the older motors doesn't have the holes for the cowl mounts. I can drill and tap the older ones but if I can use the 200 tuner plate it would be easier.

if one has tha "pin" its called a pre-load gear case.. only accepts pre-load parts, won't interchange with anything else...they are justa a little weaker than later stuff but should be ok with tha 2.0.... use tha adapter and tuner from what your callin' a 200... no cowl bracket drillin' required..

I also used the horizontal intake from this motor including the carb linkages. I still have to figure out which carbs were for which motor but they all look the same externally so I should be able to use the 150 carbs, I haven't looked at the choke systems yet but I know the old carbs were different than the rest. The 200 has the oil tank and injection drive as well as all the electronics that might go with that. I don't think the 1987 had that but I'm not sure. I really don't mind running premix though and just capping that off. I don't really trust those injection systems anyways.

tha carbs should have a wh xx number stamped on top flange.. can go from there... if not, its to tha parts break down... pre mix...

I have a pretty good parts shop to call but they aren't really mechanics so they are great with cross referencing parts and figuring out what parts should be on certain motors but they have a hard time with figuring out what is compatible although they are happy to call their reps and ask. But I'd like to do as much research as I can myself before that.

Jimmbo:

I completely forgot they changed over the hp ratings. Yes that makes sense that the 175 would be almost the same as the 150 of the different rating system.

I guess the most important thing is the internals of the '95 135. Is there going to be a difference in ports or internal channels from that to the 1987 150 being as the '95 is considered a "fat block"? From the parts diagrams between the '95 135 vs '95 150 the only real difference is jetting and the heads. The 135 has 18787 heads and the 150 has 18488 heads. I was planning to shave the heads to compensate. I could be wrong but that's all I've noticed so far. Again this is between 1995 models not the 1987 150, I haven't been able to find as good a reference for that year.

your stuck with heads from '91 up (dowel pins).. tha internals are different even though all 2.0's 135/150's ('83 up) are piston port motors and ported tha same... tha difference comes with center mains from '91 up, went to larger O.D. then in '94 tha rods and pistons changed from bottom guided to top guided.. some older stuff can be run in tha fat block ('91 up) but that said, ya gotta really do ya home work ta know what will and/or whats gotta be done ta run that stuff!....

Thanks again for all the help and responses.

Reefsider