'99 135hp Optimax - Losing compression-new powerhead???

[barryll]

I'm losing compression on my '99 135hp Optimax and the marina told me I would eventually need a new powerhead. Does this sound correct? Is this my only option?

------6/2008---6/2009

#1-----124-------95
#2-----112------100
#3-----125------105
#4-----114-------85
#5-----125------100
#6-----114-------90


Thanks in advance,
Barry L

 

[Faztbullet]

Re: '99 135hp Optimax - Losing compression-new powerhead???

Unless they have a new one in stock a replacement powerhead is NLA from Mercury. I would have it rebuilt by someone that works on optimax motors and price would be cheaper this way.

 

[barryll]

Re: '99 135hp Optimax - Losing compression-new powerhead???

Unless they have a new one in stock a replacement powerhead is NLA from Mercury. I would have it rebuilt by someone that works on optimax motors and price would be cheaper this way.

Thanks much for the info! I just got a quote from a local service center that said they use remaned powerheads from Mercury because it's just to costly to rebuild. The price was $4999. Good price???

I do travel down the I-75 corridor when I go south for the winter so I can be flexible as to where I get this work done. We winter around the Greenville/Anderson SC area and would welcome suggestions as to any good Mercury Optimax service repair centers I could call for estimates. Thanks again)

(oh yea, what does NLA mean and I know what you mean about finding someone that knows Optimax's because they are a little more quirky)

 

[j_martin]

Re: '99 135hp Optimax - Losing compression-new powerhead???

Thanks much for the info! I just got a quote from a local service center that said they use remaned powerheads from Mercury because it's just to costly to rebuild. The price was $4999. Good price???

I do travel down the I-75 corridor when I go south for the winter so I can be flexible as to where I get this work done. We winter around the Greenville/Anderson SC area and would welcome suggestions as to any good Mercury Optimax service repair centers I could call for estimates. Thanks again)

(oh yea, what does NLA mean and I know what you mean about finding someone that knows Optimax's because they are a little more quirky)

NLA means No Longer Available. Be sure you aren't getting one of the cheap remans at a high price.

You should get a second opinion. The low compression is a very bad sign, but if there's no significant cylinder wall damage, and it's just stuck rings, it might respond to fuel treatment or a decarb session.

hope it helps
John

 

[mikeneal]

Re: '99 135hp Optimax - Losing compression-new powerhead???

Ditto, try to decarb it, you might get way lucky and just have gummed up rings.

 

[barryll]

Re: '99 135hp Optimax - Losing compression-new powerhead???

NLA means No Longer Available. Be sure you aren't getting one of the cheap remans at a high price.

You should get a second opinion. The low compression is a very bad sign, but if there's no significant cylinder wall damage, and it's just stuck rings, it might respond to fuel treatment or a decarb session.

hope it helps
John

This years readings are with the use of fuel treatment and I'm not sure a decarb is relevant with a fuel injection system............but I'm no mechanic and don't understand some of the jargon. I have got 3 or 4 estimates and they are close. I talked to the place that took both reading (they also had the heads off just to check previous work that they did and the cylinders are good, at least since last June) and he said that buying the reman would be the high end price and they would like to tear it down first thinking the rebuild would be cheaper if everything else was in good shape. He lowers the hourly rate by $20 an hour in the slow season to increase business and try an keep all the mechanic's employed. I'm waiting on his return call and adding it to the option list.

 

[barryll]

Re: '99 135hp Optimax - Losing compression-new powerhead???

Ditto, try to decarb it, you might get way lucky and just have gummed up rings.

Thanks for the encouragement

 

[Jeff_G]

Re: '99 135hp Optimax - Losing compression-new powerhead???

I would be willing to bet you have nothing more than carbon build up on the rings. Go buy some Mercury Quickleen and some PowerTune and run it through the engine. You just may be able to save yourself a few thousand dollars.
If the rings are the only problem, cylinders in spec then they will just replace the rings, gaskets and seals.
I work on the all the time. It can't hurt to decarbon the engine and would be the first thing I would tell my customer, not an immediate powerhead rebuild or replacement. Sounds like they are drumming up winter business already.

 

[barryll]

Re: '99 135hp Optimax - Losing compression-new powerhead???

This years readings are with the use of fuel treatment and I'm not sure a decarb is relevant with a fuel injection system............but I'm no mechanic and don't understand some of the jargon.

Oh boy, I bet you mechanics got a kick out of that one.............decarb means decarbonization........(nothing to do with a carburetor, duh!) :redface:

I would be willing to bet you have nothing more than carbon build up on the rings. Go buy some Mercury Quickleen and some PowerTune and run it through the engine. You just may be able to save yourself a few thousand dollars.
If the rings are the only problem, cylinders in spec then they will just replace the rings, gaskets and seals.
I work on the all the time. It can't hurt to decarbon the engine and would be the first thing I would tell my customer, not an immediate powerhead rebuild or replacement. Sounds like they are drumming up winter business already.

You bet I'll try that first..............any tips or is it a "no brainer - follow the instructions" kind of thing. I would of course take another reading before, as I have put a lot of hours on the engine since June (fished Saginaw Bay/Lake Huron and a typical run time average was about 20 to 40 miles @ 40 days).

What would I be looking at after a decarbon session?

 

[jeff_smith_0423]

Re: '99 135hp Optimax - Losing compression-new powerhead???

If a full on "shock-treatment" decarb doesn't bring those numbers up, I'm afraid it's just getting tired and will need to be rebuilt or replaced.

Sounds like you got a LOT of hours out of that Optimax. The original ones were not known for their longevity.

 

[Jeff_G]

Re: '99 135hp Optimax - Losing compression-new powerhead???

About the only thing that would cause that is sticking rings. If the engine was severely overheated some warping of the cylinders is possible, not likely though. The American manufacturers use harder cylinder liners so they don't show wear like some of the other engines.

Try the PowerTune and Quickleen and see what happens. Follow the label directions. You may need to use the PowerTune a couple of times. If the pistons are really coked and rings sticking you may need to have the engine rebuilt (re-ringed).

 

[barryll]

Re: '99 135hp Optimax - Losing compression-new powerhead???

Sounds like you got a LOT of hours out of that Optimax. The original ones were not known for their longevity.

I don't know what is considered a lot of hours (last official hours as of June 08) was 409 hours. I did install an hour meter that has 157 hours on it that I just checked - so unofficially I would guess right around 525 hours (it was installed spring 08). I usually run around 3500/4000 rpms in decent weather and that seems to be it's sweat spot - 4.5 to 6 gph. Does that sound good to you?

 

[barryll]

Re: '99 135hp Optimax - Losing compression-new powerhead???

About the only thing that would cause that is sticking rings. If the engine was severely overheated some warping of the cylinders is possible, not likely though. The American manufacturers use harder cylinder liners so they don't show wear like some of the other engines.

Try the PowerTune and Quickleen and see what happens. Follow the label directions. You may need to use the PowerTune a couple of times. If the pistons are really coked and rings sticking you may need to have the engine rebuilt (re-ringed).

Thanks for your input. I'll be down that way some time next week and try your suggestions.

Thanks everyone for your input and suggestions!!!!!

When I try the decarb and will post back the results, might be in a couple weeks though as I don't know how long my honey do list will be.