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Merc 120, 140, 170 or 4.3??

JRJ1

JRJ1

New member
Hello new guy to the forum here and have a question that I hope will start my activity here :)

I have this project boat it is a 201 Admiral Galaxy cuddy. It currently has a merc 140 in it that came from the factory. The motor is siezed.. so going to purchase a new one in the coming days. So I am wondering.. It seems there is no shortage of used 120 engines. Would this really dog this boat being that it that much less than stock and I was told that the 140 on this is underpower for the size and weight of the boat. So, I can find a 140 as well, but will this boat run better with a 170 or even a V6? I have a great deal on a 4.3 and complete outdrive if I want to go that route. The boat is gutted, new floors in, ready for power. Just wondering if I should up the power or if the 120 or 140 would do ok. I would like this boat to at least get up into the 35-40mph range.

Any input would be appreciated and look forward to learning more from this group!
 
Ayuh,... I'd go with the 3.0l, or Better yet, the 4.3l...
The 470 is out of the question,+ the 120hp will be even more Under-powered...
 
You have several issues to consider.

A four cyclinder motor in a 20 ft boat no matter what HP is under powered. It was done as a cost thing not a propperly powered boat.

A 120, 140 , 170 (470) all mount with one motor mount in the front.

All v8's or v6's have motor mounts on the sides of the motors.

So if a boat is biult with a 4 cyclinder in mind it will not have the stringers on the left and right to support the motor mounts for a v6 or v8.

Now if you have the mechanical ability then you may be able to overcome this issue. If not then you are stuck with a four cylinder design with a front motor mount.
 
Do not get a 170, 470 or whatever else it is called. Simple as that. If you have to go with a 6 or 8 then you need everything back from the flywheel, inside and what hangs off the back.

Understand what i just posted ?
 
If you're at all handy, you could do what I did. I had an 18' aluminum boat with a 120 and it was OK----used it for years. It topped out at about 37 mph. I always wanted more power, however. I bought a 6 cylinder 165 hp with outdrive and installed it. Everything bolted right in except the front mount. It wasn't too hard to move it forward enough to fit the 6 cylinder. I also added on to the back of the engine cover which wasn't hard to do and had it reupholstered. It really comes on plane now and tops our at 45 mph.

Remember that the gearing in the top bevel gear set is different between the 120/140 and the 165 engines although you might be OK with the 140 gears and just change prop pitch to handle the extra power.
 
Thanks for all the input!
The 120 is out.
I have heard good and bad on the 470s plus they are really pricey.. so.. just not going there.
Dont think I really want to get into glassing in new engine mounting blocks.. so the v-6 is out.
I have plenty of forward room for an inline 6cyl. the four cylinder front engine mount is about 10 inches away from the
cross member from the stringers.. so then, 427435, I would be looking for a merc 165 6cyl.? are these hard to come by?
I need an entire outdrive as well so I will get whatever I can to match if I go this route.
Thanks!
 
this 20 ft boat will require a 170 hp or more for you to be happy. unless you like to boat with no passengers and equiptment.

the 470 4cyl will do the job , but it is out dated I would not use this .like you say too expensive.

find another boat with a blown motor that has this setup for a 6 or small 8 cyl.
 
I put an ad on my local Craigslist and a guy contacted me this morning with a mercruiser straight 6 in an older boat, motor runs, no outdrive already sold it. Will not sell me just the motor, have to take the whole boat however he says $200 get it out of his yard.
Gonna go check it out tomorrow. I am leary, seems fairly straight up but we will see.
 
with the time of year and the current economic conditions you should have no problem locating a used motor that runs. take your time !
 
I think something will come through.. Since I posted this, I got about 4 more emails with these motors. One in particular I wonder about.
Engine and outdrive complete $500 garage kept for 8 years, is this too long for an engine to sit? Still going to check out the $200 one in the morning.
Thanks for helping me out here !
 
If you can't run it with muffs, don't buy it. The one in the garage for 8 years is well worth a look. I had the 120 that I took out of my boat in a garage for 5-6 years and the compression checked out fine.
 
Ok, no luck.. this $200 one.. the guy is a dirtbag. Motor is probably good, got it turn over was just sitting for a while.. then decides because its now known its most likely good he doesnt want to sell it.. but was ok with selling me junk. Wasted my time taking a day off work.
Havent heard back from the other guy with the one in storage, so we will see what happens. I just cant drop a couple grand on a boat motor for a 1986 boat. If I am gonna spend a couple thousand, I will spend 3-4 thousand and buy a decent boat running. I already have a small cruiser, just want something easily trailerable to take family to the lakes as my boat is docked at a Marina. The project route is a good time for my teenage son and I to relate to a mutual interest, so buying a boat kinda defeats my other motive here. The other offers were all bunk too, all junkers... or how about this one.. soft siezed? I think that should mean junk right? I got time however and winter is on the way.. I am thinking come December/Jan some of the $1500 motors might be more like $600.. We do have a really nice older Seadoo GTX we might sell or trade for a motor, so there are plenty of options.
I agree J Cat, there is no pressure here.
 
you have 9 months to get this resolved. back in the 1975 depression I got a great deal on a boat. 10 years later I sold that boat for a 100% profit !
 
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