need info on what oil I can use
and any history for the 2000 150HP Optimax / good or bad
I took the plugs out – and i’m sure they have never been change – still black paint on them
Thanks in advance
U guys on this site are very honest on issues with products 
The 150 Opti is a solid motor. 12 year old plugs kinda proves it!
If you are a new owner, change the plugs, get the water pump/impeller changed. New fuel filter.
If you have a tech pull the error codes and total hours go from there. 200+ hours Change out the compressor belt. Other than that, run it like you stole it baby! 
I own a 2003. I run the Merc or Quicksilver Opti oil. Make sure the label specifically says ok for optimax. There is EFI and Opti oil. I always use the Opti. You will be pleasantly surprised how little oil this motor ueses!
-J.
X2. Great motor
Bought mine new in 2000. Changed plugs twice, just because. Water pump once after beaching it.(do not ask) Run premium or ethanol. Carry seafoam and add to gas if ever starts burping on troll and comes right out of it. Great motor and uses 1/4 the oil of my 90 yamaha. Been great motor.
I own a 2000 135 Opti same block, as Jordon said get the water pump replaced complete kit. Opti`s are low pressure high volume water pumps at idle they only hold about 2-31/2 lbs pressure. The water pump on Opti`s are a maintenance issue depending on use, some change every year some every other year. There was all so updates to the thermostats I would check and see if it was done. They have all so changed plug numbers for the early Opti`s so check with dealer for correct number Do not buy plugs from a dealer you can get them cheaper thru many parts store about 13-17$ apiece.
NEVER NEVER NEVER I will say it again NEVER put the hammer down when the engine is not up to temp. The Opti`s are a close tolerance engine the pistons expand faster then the cylinder walls when cold. Many Optis have been blown from cold seize. I have run Amsoil HP in my since I have owned it not narry an issue. I have run 10% ethenal for ever in mine and not a problem and I too run Seafoam regularly.
They are great motors when properly run and maintained sipps gas and oil unless the pedal to the metal then they all can suck some series petroleum products.
lots of good info so far – Yes I do own the motor
and yes sounds like good idea to have water pump done and have hooked up and see about hours on it – THANKS
– the book says Champion plugs – Number — QC12GMC
can any of U verify if this is the current one to use or at least be able to tell me what you are using in your 150’s
I still have these plugs out and that is the number on them
Not that easy to change there is a couple lower holes that are real pain in the 
I believe Mercury changed the recommendation a few years ago, and now recommend only using iridium plugs in the optis, I just changed mine and yes they are a pain to change.
Also, I only ever use Mercury Optimax oil, these motors use so little oil it’s not worth trying to save a few bucks on a gallon of oil.
As wadsworth said use the Iridium plugs not cheap but it will run better NGK`s. After installing the Iridium no need to change them again unless a plug issue comes up. If you gap the Iridium’s be darn careful you bend that tiny center electrode they are toast. I did have an issue with two new plugs that were bad so keep that in mind if a miss develops after changing out the plugs.
Did I mention NEVER put the hammer down on a cold Opti.
Pretty sure these are the current recommended plugs
-IZFR5G@ .032-.033″ for Standard Opti’s 135-225HP
Lots of other good advice.
I would definitely avoid gas that comes from corn if you can … 
I wouldn’t mess with trying to gap these plugs, my understanding is they come from the factory with the correct gap for the optis. I have changed mine and never gapped them and my motor runs like brand new.
Another note on changing them, my motor is a 135, a V6 with the same block as your 150, and I highly recommend taking the lower cowling off to change the bottom two plugs, knuckles and extensions can put a lot of indirect pressure on the plug, none of us want to know what it costs to repair or replace an aluminum head because we stripped it out or broke a plug off and damaged the aluminum.
Remember, this is a job you shouldn’t have to do again for a while, so take your time and do it right, there are torque specs for the plugs as well, I can’t remember what they are, but there is a mercury forum at bass boat central full of information, as well as Mercury Techs who post there and answer questions on a daily basis.
Quote:
As wadsworth said use the Iridium plugs not cheap but it will run better NGK`s. After installing the Iridium no need to change them again unless a plug issue comes up. If you gap the Iridium’s be darn careful you bend that tiny center electrode they are toast. I did have an issue with two new plugs that were bad so keep that in mind if a miss develops after changing out the plugs.
Did I mention NEVER put the hammer down on a cold Opti.
Just in case you haven’t heard it enough…….never, ever,never, never, ever hammer on a cold opti. I have my boat & opti serviced every fall and then my merc tech guy gets evrything hooked up & running for me again in the spring. He tells me that multiple times every time he services my motor. Absolutely love my opti! Don’t want to be an alarmist, but weren’t the late 1990’s & early 2000’s the years that there were some issues with the bigger optis? My buddy had a 150 opti that blew its powerhead. If I remember, it was a ’99 or ’00. I would assume if there were potential issues, a good tech could catch it before there were bigger issues. My tech told me the issues result from some of the cylinders heating up faster than others, therefore the need for a warmed up motor.
This is very good advice, Mercury recommends you warm the engine up to 130 degrees before taking off, I always watch the temp on my smartcraft guages to make sure it’s warmed up sufficiently before taking off.
Quote:
Just in case you haven’t heard it enough…….never, ever,never, never, ever hammer on a cold opti. I have my boat & opti serviced every fall and then my merc tech guy gets evrything hooked up & running for me again in the spring. He tells me that multiple times every time he services my motor. Absolutely love my opti! Don’t want to be an alarmist, but weren’t the late 1990’s & early 2000’s the years that there were some issues with the bigger optis? My buddy had a 150 opti that blew its powerhead. If I remember, it was a ’99 or ’00. I would assume if there were potential issues, a good tech could catch it before there were bigger issues. My tech told me the issues result from some of the cylinders heating up faster than others, therefore the need for a warmed up motor.
Quote:
Just in case you haven’t heard it enough…….never, ever,never, never, ever hammer on a cold opti. I have my boat & opti serviced every fall and then my merc tech guy gets evrything hooked up & running for me again in the spring. He tells me that multiple times every time he services my motor. Absolutely love my opti! Don’t want to be an alarmist, but weren’t the late 1990’s & early 2000’s the years that there were some issues with the bigger optis? My buddy had a 150 opti that blew its powerhead. If I remember, it was a ’99 or ’00. I would assume if there were potential issues, a good tech could catch it before there were bigger issues. My tech told me the issues result from some of the cylinders heating up faster than others, therefore the need for a warmed up motor.
You are correct the big block Opti`s did have an issue but the small block V6`s 135-150-175 were pretty much rock solid. Unless the hammer goes down before up to temp as you stated.
Edited to add As mentioned the port side lower plug can be a bear. I use a peace of fuel line stuck over the plug to get it started darn easy to cross thread and strip out the plug hole, if it does not turn in easy try again.
Quote:
You are correct the big block Opti`s did have an issue but the small block V6`s 135-150-175 were pretty much rock solid.
X2. The 150 block is solid.
I would’nt put the hammer down on any big motor before it warms up. Boat, car, wheeler….heck, I’ll even wait for the lawn mower to warm up!
-J.
Agreeing with all said. Was with my buddy when his ’99 or ’00 150 opti blew the powerhead. Don’t want to hear that sound or have that dead in the water feeling again. Love my ’07 225 opti – nothing better than that opti growl!
I just searched the forums to find this info about my 1998 150 opti. I found everything(I hope) I needed to know. I’m going to take it a Mercury dealer and have the water pump impeller service and the codes read and I might as well spend some of your money and put new plugs in, oh wait it’s my money, check the temp sensors and maybe see what else they recommend.I bought some opti oil at the dealer and he said regular quicksilver oil will foul the DFI injectors. Great read thanks everyone. matt
Quicksilver DFI oil works. I don’t know of anyone locally who sells the opti oil bulk, so I buy the quicksilver DFI. My merc tech says it is just fine, that’s what he runs through his opti.
You must be logged in to reply to this topic.
