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Rebuild 2006 Optimax 150

Posted: Wed Jul 18, 2018 5:06 pm
by quickenberger
It has been a while since posting, mainly since restoring the 19ft Sentry. Things have been going quite well. So far the boat has been on Flaming Gorge dozens of times, and we trailered it to Dana Point, CA and fished around there and crossed to Catalina and back. Not too bad for my first ocean run.

The 2006 optimax 150 is tired though and I'd like to see if someone has had good success with rebuilding the powerhead and who they'd recommend to do the actual powerhead rebuild. This powerhead has been used in freshwater its whole life (except for the 3 days in the Pacific) and I'd like to have that particular block rebuilt and sent back.

Let me know if there are reputable shops that will do a good job.
Thank you,

Re: Recommendation for Company to Rebuild 2006 Optimax 150

Posted: Wed Jul 18, 2018 5:15 pm
by Jefecinco
Recommend you check with your Mercury Dealer to see if there are any factory rebuilt exchange Optimax power heads available. If none are available I would look for a dealer with Mercury certified mechanics and a very good local reputation.

What is wrong with your engine that requires a rebuilt power head?

Re: Recommendation for Company to Rebuild 2006 Optimax 150

Posted: Wed Jul 18, 2018 5:49 pm
by quickenberger
I am getting ~70 psi compression on each cylinder. Hour meter is 1738 last time I ran it.

Re: Recommendation for Company to Rebuild 2006 Optimax 150

Posted: Thu Jul 19, 2018 10:02 am
by Jefecinco
From your comment I suspect you don't need a rebuild but perhaps an upper cylinder "overhaul". Unless you are an experienced mechanic you should have a compression test done by some one with experience. A leak down test may also be indicated.

Assuming your professionaly tested compression test results are below specification the solution could be nothing more than replacement piston rings and a cylinder honing job which is relatively inexpensive and very effective.

I would take the engine to a reputable Mercury Certified mechanic for evaluation and recommendations.

Engine rebuilds done in the field are often not done to the level that a consumer would expect. Usually, at best, the final product is an engine overhaul rather than a rebuild. This is one area where the buyer should most definitely beware.

Re: Recommendation for Company to Rebuild 2006 Optimax 150

Posted: Fri Jul 20, 2018 11:06 am
by quickenberger
I was thinking it would be best to rebore the cylinders .020" over and get new pistons, bearings, seals etc. I'm not sure about a top end overhaul since I don't know the conditions of the cylinder walls or the condition of the piston skirts. If there scuffs on piston skirts or grooves where the piston reaches TDC then I think it would be best to rebore. Nobody rebores outboard blocks in my area so I'd have to send it out.

I have used differential compression testers before, like this one, just not yet with this boat engine.

Re: Recommendation for Company to Rebuild 2006 Optimax 150

Posted: Fri Jul 20, 2018 1:41 pm
by dtmackey
Compression does sound a bit low. Make sure the compression gauge is accurate and you are not getting a false reading. You can also bore scope the cylinder to look for signs of scoring.

A remanufactured powerhead is the ideal way to go and the dealer or mechanic would simply dress the motor with fuel and electrical from your existing motor and test run (I make it sound too easy).

If you are thinking of freshening up the top end with a hone and rings, I'd argue in favor of a rebuild with machine work and a 0.020" bore, new pistons assemblies, rod bearings, ride bolts, crank bearings and gaskets. The labor to get to the point of a hone and re-ring is close to the same as a full rebuild and the additional cost in parts is minimal (at dealer cost) considering the scope of the overall project and with over 1700 hours, you then start questioning the life remaining of the bearings. I'd also give consideration to replacing the reeds since metal reeds fatigue over time and I'd hate to hear of a reed cracked on a rebuilt motor wiping out a cylinder.

Dealer cost on a rebuild kit is $741, boring can range from $50 - $100 per cylinder depending on where it's performed. A reman powerhead dealer cost is roughly $2,595 and list to you would run $3,892 plus labor. My guess at a dealer you are looking at $5,000 - $5,500 for a full reman powerhead swap. A rebuild at dealer I've seen run about the same as a reman swap due to number of labor hours and the work comes down to the tech and the machine shop they contract with and their competency.

If you need a machine shop recommendation for the machine work side of the rebuild, I can point you toward an outfit I've used in FL for over 20 years and the work they've performed for me on many outboards has always been top notch. They only perform machine work on outboards, so this eliminates the Jack of all trades concerns.


Re: Rebuild 2006 Optimax 150

Posted: Sun Jul 22, 2018 2:27 pm
by Phil T
If you do "need" a rebuild, don't. Not worth the money given the age. Would guesstimate a rebuild is 1/2 the price of a new motor. That still leaves the lower unit, tilt & trim etc being 12 years old.

Run her till she blows and buy new. Jacos Marine lists the Mercury 150 FourStroke for 10k in the crate.

1700 hrs or more is a good run for an engine. Most owners are in the hundreds.

Re: Rebuild 2006 Optimax 150

Posted: Mon Jul 30, 2018 6:00 pm
by quickenberger
Thanks Phil,
At ~$3K for me removing the powerhead and sending it off, putting it back on and only one year warranty on just the powerhead, there are a few more things to consider. One is replacing the injectors (not bad now but will fail sometime). With 6 air injectors, 6 fuel injectors, that adds up to about $3-4K. Then there is the air compressor at about $700. There is the solenoid oil pump at about $600. It is looking like the best thing is to look at a new outboard. I've never heard of the Jaco Marine website.
Off topic question: How have the Merc 150 XLPT engines held up so far? That is the one referenced by Phil on the Jaco's website. Do they specialize in high volume-low margin distribution? Asking the local marine dealer he guessed at about $13K for a new engine.