Question about used Optimax 150's - The Hull Truth

slief · 09-25-2008, 12:28 PM

I am looking at pruchasing a 1999 Glacier bay powered with twin Optimax 150's. One is a 1999 and the other is a 2001. Both have around 550 hours on them. I was wondering what I should be checking on these engines to confirm their fuctionality.

I know I need to do a compression check. I assume it is as simple as pulling all the plugs, installing the compression guage into the plug hole and bumping the engine over. Is that correct? What kind of compression should I be looking for?

Also, I know I need to check the oil quality for water. I assume I would just tip the engine up remove the drain plug and tilt it down enough so that some oil drips out??

Any suggestions would be greatfully appreciated as I know nothing about the Optimax engines.

Best Regards,
Scott Leif

A1 Outboard · 09-25-2008, 03:13 PM

Optimax engines are very complicated compared to the traditional carbureted 2-strokes. Becaue of their high tech design and the critical adjustments and settings, hire a trained and experienced Optimax mechanic to go over the motor, check it out with the laptop and diagnostic programming, and give you a printout of the engine history. Fuel and air pressure tests should be performed and well as a water test if possible.

Compression readings should be within 15# of each other and be very suspicious if 5 are very close and one is 10-15# different. Unless they were serviced recently and there are documents to prove it, figure on spending some bucks to have them serviced completely including water pumps, thermostats, and pressure relief valve.

slief · 09-25-2008, 03:22 PM

Thanks A1! I appreciate the info.. What should I expect to spend on the service for 2 of them assuming it was a typical service? Unfortunately, I cant find a local mobile Mercury tech who can take a look at it prior to the purchase so I will be limited an on water test and a compression test. I did find a semi local service place to take it to which I am planning on after I buy the boat or possibly prior if I can work it would with the seller.

You wouldnt happen to know any good mercury service locations in Ventura or Santa Barbara would you???

Thanks again!

slief · 09-25-2008, 04:50 PM

Also, What kind of compression numbers are good? I think on another 2 stroke I had it was 120PSI..

A1 Outboard · 09-25-2008, 07:23 PM

There is no compression number as the accuracy of the gauge, the cranking rpm, and the amount of oil on the cylinder walls all affect the pressure. Just make sure all are within 15# of each other.

These motors require someone trained on them and with access to a DDT or better yet a laptop for adjusting, troubleshooting, and for regular maintenance and error reporting. An "I can fix anything" type of "mechanic" is not what you want working on these.

slief · 09-25-2008, 11:28 PM

My plan will be to bring the boat to a Mercury certified repair shop after I see it first.. The info you gave me will at least give me some guidelines for when I go to look at the boat. I planned on doing the compression check myself along with checking the oil for water. We will also do a sea trial so I will be able to get a good idea if they run and idle well as well and if the impellers are working.

Thanks for the info! That was a big help!

Best Regards,
Scott