94 Merc Mariner 175 question...

any opinions on its oil injection system? keep it or junk it and premix? Also any idea on what psi the compression should be? I am going on sat to check the motor out and will be doing a compression test before I purchase it. Other things I should look for???
 
Cross flow and loopers are OMC products as far as I know, I have a looper 225 Evinrude.

As far as oil injection goes, IMO Junk it!! I lost a motor to it and I will not lose another!
 
V20 SEAHAWK said:
Is my 1994 Mariner 175 carb. a cross flow or loop system? :confused:
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def a looper...i dont beleive merc ever made a 175 cross. the highest hp they made that might have been a cross were the old inline 6's. and they made a 150 at the most and i beelive a hotter version of the 150 which still was the same block config. yours is most likely a 2.5 liter looper. should be around 120-125 stock. also oil inj on those engines if it has a remote tank are ok untill the nylon gear on the crank goes out then the engine will tell you your running out of oil. also make sure you change the oil check valve if you are keeping the inj.

also pull the lower plug on the gearcase and smell the oil and look for metal.
 
Check out the color of the lower unit oil. It should look like basically new oil. If it is milky, there are leaky seals and you are getting water in the lower unit.
 
Like stated above, definately a looper. It could either be a 2L or 2.5L in a 175HP MERC. IIRC a 2L should have around 100 pounds of compression, and a 2.5L FEESHIN motor should have around 120-130(my XRI has 128). I personally junked the oil injection system on my 95 150 MERC 2.5L. Read to many stories of the nylon crank gear breaking. Or even worse it starts to strip the gear and the pump slows down, but not enough to set the alarm off. When I removed mine the metal gear that rode against the nylon crank gear was worn to the point it was razor sharp(I could have shaved with it). Also look under the flywheel to see if the magnets are loose. And if you run it, don't freak out when it doesn't shoot water out the piss hole right away. The MERC system only pees when the T-stats are open.
 
if its a 2.0 175 they made it from 76-81. i wouldnt mess with it. if its a 2.4 then it either a 78-91 a lot better than the older ones but still not a great as the 2.5's. if its a 2.5 its will be 1992-on. probably the one you are looking at.
 
thanks guys... I actually decided on another boat. Still a V20, but a 1985 with a 200hp Johnson Ocean Runner. This boat dosn't need a new fuel tank right away like the other boat would and it is in better shape overall. (comes with 6mos dry stack storage too :D ) going to compression test and run this one on Sat.

wish me luck... :jump:
 
That motor has lower compression b/c of the relief holes . . . so don't be alarmed when you see 100psi or less in all 6 cylinders. As long it's even . . . then your good.
 
Probably stuck rings (65 and 80) and a bad powerpack or stator . . . it's a good negotiating point. I'm rebuilding one now . . . pretty cool motors.

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There not that bad to build either. The MOST important thing to look for is a good hull. This is almost the whole battle right there. I can't tell you how many V-20's I've looked at with bad transoms, seperating knee supports, and spongy decks. If the hull's good negotiate it. At least then you can build up an engine that you will know is good.
 
I would, but I don't know anything about outboard motors (i know plenty about cars, just not boats) and I live in an apartment complex and have no room to work on the motor... If I didn't have to mess with the motor I'd have it by now... it just adds to the amount of work I'd have to put into it :huh:
 
If he'll let you pull the heads and check out the cylinder walls on those two low cylinders for scoring or a bad head gasket(s) . . . then you might luck out. He's going to have to do it anyways . . . cause of 60psi in the one. If there's no aluminum skuff or scoring . . . you might be able to replace the head gasket(s) and decarb (power tune) . . . it's possible that will be enough to break down the carbon, free ring and restore compression.
 
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