Thoughts on 1984 Merc 150 ??????

[Aquamaniac]

Wonder if anyone can shed some light on this motor......reliable? too fuel hungry? ease of repairs?
Thanks!

[Aquamaniac]

Sorry, forgot to mention.....it is on a 91 200 Striper.

[GoneFission]

An 84 Merc 150 is a V-6, 2 liter engine with carbs.  It should have the model designation EXLPTO for 25" shaft or ELPTO for 20" shaft length.  
E= Electric start
XL or L = Shaft length
PT = Power trim/tilt
O = Oil injection

These engines are solid, reliable engines with just a couple weaknesses.  The ignition system is a dual system with separate switchboxes running each bank of 3 cylinders.  So it will run even if a switchbox fails.  Stators are a common problem - Mercury is now up to version 36 on the stator.  A new stator runs about $150 online, and switchboxes around $100 each online.  3 charging options are available: 9 amp, 16 amp, and 40 amp - the rectifier sometimes goes out - easy fix for about $20 online.  The 40 amp system is fairly rare - you see it most on 20 inch bass boat motors.  You can upgrade a 9 amp stator to 16 amp, but not to 40 amp.          

By 1984, Mercury had moved to the second-generation oil injection system that is very reliable, and these engines love to run!  WOT with the right prop should be around 5500-5800, and it will run all day at 5000.  The 2 liter engine has the same stroke as the 2.4, but uses a smaller diameter piston.  This long-stroke setup gives good torque and most 150s will dyno closer to 160-165HP if they are running right.  

Fuel economy should be about by the numbers - around 14-15 gph at WOT.  Expect about 30% more fuel consumption in mid-range running compared to a modern engine with electronic fuel injection.  These are low-maintenance motors - change the lower unit oil every year, water pump every year or two, and spark plugs every year or two and that's about it...  

[icemanbryan]

My opinion,
good engine.
However,
it is a 30 yo engine.
Check the usual items you would check when buying.
If it checks out, should be fine, yeah?

[wingtime]

Actually it is now a 30 year old motor.     But if it's clean and has good compression I wouldn't rule it out.  It is a easy motor to work on yourself.  Can't say the same for today's electronic motors.  Heck look at it this wat...  It's lasted this darn long...

[icemanbryan]

My bad.
I say check it out, can't hurt.

[Aquamaniac]

Thanks guys.....headed there today.

[Aquamaniac]

OK....checked it out today.
Cold started well and ran OK. Shifted well.
Checked compression.....ranged from 105 to 115 ...no glaring bad cylinders.

The BAD news.....Only got "click click click" with tilt/trim.  :(
He said it worked fine when last in the water (3 months ago) and felt it was the solenoids.
This is the external unit in right rear corner by transom.
Any thoughts?????? Would love a quick and dirty method to sort out what needs to be replaced.
Thanks!

[futch13]

Jump the solenoids like you would trying to start a car.  Blue wires are up, and green wires are down.  If they work, switch or wiring bad, if not then solenoids.  Also ck the grounds on solenoids and trim motor to make sure they are tight and clean before replacing anything.