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AndyNegus94

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Well guys I've got an 86 ranger 373v and the old 2 150hp mercury on it has definitely seen better days, even on the hottest of days it takes 5-10 minutes to start and in the cold I'm lucky to get it going at all. im looking to get a fuel injected motor just not sure what all will need to be changed to run the new motor. will I be able to use any of the old controls or will I have to buy all new? Also will have to go to a hydraulic steering system. I found an 07 optimax 150hp with 175 hours for $4800, is that a good deal? are they good reliable motors or should I look for      something else? Thanks for in advance for any help guys, it's very appreciated!! 

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Going from an 86 to a late model motor may create several problems but I'm not versed on the Merc's well enough to say for sure what all.

The first is, I'm not sure the transom mount on that 86 has the same bolt pattern as the newer one.  Somewhere along the way years back Mercury changed. 

As for the controls. Again, might run into problems.  As a minimum, most likely the wiring harness will be different.  If they are, you will need to see if that make and adapter or have to replace the whole thing. 

If you go with a different make than a Merc, you will almost have to change controls to match the make motor.

If you have dual cable steering and the cable are good and it turns fairly easily, that should work on any motor you put on it.  If the cables are bad or if it's not dual cable, it needs to be repaired/replaced.  If that's the case, it doesn't cost that much more to go ahead and upgrade to hydraulic steering.

Before sinking a large sum of money into a boat that old, I hope you have checked it out very well.  Making sure the transom and floors an nice and firm.

As for the Optimax itself, do your research on line.  For several years they had major issues with reliability and had the nickname Opti-Pop.  Not sure when they started making the more reliable motors.

Sorry for the vague answers and hopefully, someone that knows the FACTS about swapping the early Merc for a late model can help.  Scream and Fly and Boat Setup * has a lot of people knowledgeable on your questions.

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Before 02 there were Opti problems.  Since then not so much.  The key to an Opti is being sure to warm it up before take off.  I get mine up to 120° before I leave the launch area.  If I fish a long time on a bank in the winter I warm it up again like at the ramp.  Mine is an 02 and still going strong.

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Well I guess I'll have the boat checked out by our mechanic and see what he thinks. Id love to be able to just go out and try to find a newer boat but that's just really not in the books right now. Thanks for the help guys!

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If you have not already done so, do a compression test on that motor.  That's something you can do yourself with one of those $10 Harbor Freight gauges.  Crank it up on a hose and let it run for several minutes to get some heat in it, the cut it off and wait about 10 minutes. 

Open the throttle some so the motor can get air through the butterflies in the carbs.

Make sure the cranking battery is fully charged and strong

If you have a safety kill switch pull it so the motor won't start.  If not pull all six plug wires off and do something to ground each wire.  It can damage coils with no load on the wires.

Removing one plug at the time check each cylinder.  Cranking it over until it hits at least six times and write it down.  If you remove all six plugs to start with, it turns much easier but sometimes you run into the problem of the starter bendix kicking out every time it hits on the cylinder with the gauge in it, but if it will let you it's best to remove all six.

The bottom cylinder on that motor can be all kinds of fun to get a gauge in.  You might have to drop the low cover or if the other five are all good, just "assume" that one is also.

Once you have all your readings, there should be no more than a 5% difference between the lowest and highest.  If there is more than 10%, the motor is probably close to being ready for the salvage yard.  Even at 10% you can have running and loss of power issues and the motor is on it's last leg.  Unless you are a very good mechanic, rebuilding it is not a viable option.  Way to expensive and requires some special tools because it does not have a cylinder head and all six pistons have to go in with the crank from the bottom.

Now, if the compression is good, those a good, strong old motors and would be worth looking into getting it running right.  Maybe rebuilding carbs and having the ignition system checked out.

 

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Are you talking about the old merc I have or the opti? Also I have a compression tester so I can go ahead and test it this weekend when I have free time! 

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OOPs, sorry about that, I thought I was talking about the 1986 but I got my wires crossed along the way.  You posted it was an XR2 150 but my brain registered it as the 115 inline 6 tower of power, so disregard a lot about me saying it didn't have heads and the bottom spark plug might be a problem.   The V-6 motor is much easier than the inline to work on  

However, still follow the same procedures I stated for doing the compression check and they percentages still will be the same.   If the compression is good, you still have something you can work with, but it the numbers are off on that, there are some things you can try to do a good decrabing of it that might help, but we will chase that rabbit after the compression test.

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If I were you I might look for a good running MERC EFI motor. I had a 1998 200 EFI motor.  I purchased it new ( decided to stay efi which was bullet proof instead of OPTI which were having trouble). I ran that motor on a 20 foot Procraft for over 10 years.  Other than some minor maintenance that motor was fantastic.  It started easy, ran fast and was fairly quiet.  By the way a 150 to 200 hp use the same engine and I would figure the bolt pattern would be the same as yours. If it is not just add a 6 inch manual jack plate, the engine will appreciate the cleaner water flow.  They made the efi engines for a lot of years after mine so you should be able to find a good deal on a newer motor or even a rebuilt one from a place like Almars in Delaware.  They totally recondition them and ship all over the USA.  The steering should be about the same as yours but Sea Star Hydraulic steering was great

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Have you thought about getting a good tune up from a professional? The old mercs are very reliable when well maintained.

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I have looked all over craigslist and that opti is the only 150hp fuel injected motor I've found but I will check out almers, thank you! And I had the motor "tuned up" spring 2015 and it ran decent and started alright and sometimes idled good but after 6 months or so it started getting harder and harder to start and wouldn't idle unless revved up a little. I like to think I take good care of it and do proper maintenance but this is my first boat and I'm a little ignorant still. I mix all my gas 12.5 oz of oil per 5 gallons of fuel with QuickSilver oil and also run Biobor EB fuel treatment. 

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Silly question. Have you checked the fuel filters? I have a 76 Merc thunderbolt that did the same thing. And when started, would bog down at full throttle. I pulled the cowling of, primed the bulb and fuel was spraying out the hoses and fittings. $9 all new hoses and fittings. Also cleand filters and it runs great. Try pulling your cowling off and prime it. Could be sucking air.

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I don't claim to be very knowledgeable of the Merc's but I thought the XR2 was a 2.0 motor and the 200 was a 2.4 liter motor.  I though the XR4 was the 2.4 liter motor and I'm not sure the exhaust adapters are the same between the 2.0 and 2.4 so I would double check the facts before looking for any thing to do with swapping parts between the two. 

However, as mentioned, those XR2's happen to be one of the better motors Merc built and if it has been half way taken care of and not just totally used up, it may just need some TLC.  Before getting too concerned about looking for more motor than you think you can afford, I would suggest doing that compression test.  Then you will have a better understanding of what you have to work with.  Also, if the reading are marginal, there is a procedure I would use to decarb the motor and then check the compression again.  I've had a number of older motors that didn't look very good to start with but a little wave of a magic wand and their numbers would be right up there where they were supposed to be.  If the internals are good, the externals can be made good.

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Well once I see we have a few decent days in a row I will get the ol girl uncovered and do a compression test and check all the fuel lines and fittings! What is the ideal compression for it? And also I should've mentioned is a Mercury black max. 

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The ideal is no more than 5% difference between the highest and lowest reading.  Because of the difference in gauges and other variables, trying to put a definite number is not really practical.  It only needs to be above about 80 psi to run but I don't know what those motor had as a nominal pressure.  That was right in the early stages of them dropping the crap out of the compression so they could run that junk gas they started making us use back then. I've never seen a motor that all six cylinders wore out evenly so the main thing is the difference between them. 

I once rebuilt the engine in my old Toyota pickup because of a bad compression gauge.  The motor had 290,000 miles on it and developed a skip when cold but would quit after warming up some, but started getting worse and taking longer to quit.  It skipped all the way home for lunch one day say before I left again, I knew it was #4 cylinder so I did a quick compression test on just that one, it was 85 pounds, and I know it should have been about 160 or more.  So, that weekend I pulled it out, tore it down, had it bored, crank turned, all new parts and the next weekend put it back in.  I drove it about a week and decide to do a compression test on it to make sure all the rings had seated,   Guess what, all four cylinders had 85 pounds.   The Schrader valve in the gauge had messed up and that was all it would let it read.  When I rebuilt it, I installed new plugs so I got the old ones and looked at them, the insulator on one was cracked, that was my skip.  That's what happens when you think you know too much, and do things in a hurry, rather than the way they should be done.  However, I didn't feel to bad about it, because with almost 300K on it, it probably would not have been long before it needed it.

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Way2slow you may be correct about the xr2, my comment on the 150 to 200 comparison was in reference to the EFI motors only.  In 1998 the 150, 175, and 200's were built with the same engine block.  The main difference was in fuel calibrations so the weight of a 150 and 200 were the same.  My point was that he could expect the same reliability out of a 150 EFI as I had out of my 200 EFI.  I actually had the great experience to tour the ProCraft/Astro factory before ordering my boat. This was during the time Procraft/Astro was a Mercury Marine factory boat line.  That was way cool.  My wife and I got to detail out the order down to the thread colors in the seats!  All I had to do was wait a few months till my dealer got it in with several other winter time boat orders. The boat was a fish & ski model so it had a heavier hull with a walk through windshield and seating for five. That motor had the large gear case so the boat came with the 5th large hub Trophy 4 blade Merc ever made (not including their prototypes) according to the factory. We kept it for over ten years and it saw lakes in 5 states, and lots of Potomac River and Upper Chesapeake Bay  time as well.  Your advice on fuel lines is solid since Mercury is suggesting to change them out to the new lines and primer bulbs.  The garbage fuel we are forced to run now (ethanol or oxygenated fuel ) due to EPA is causing the insides of the lines to break apart or swell up and cause restrictions.  

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