Is this concerning.

[B A Texan]

I have a 2001 Optimax 225 (0T333823) that I took to the dealer to get trade in apprasial and they wont touch it due to compression numbers.
1-100 2-105 3-110 4-115 5-95 6-105 motor has 479 hrs
They did not do a leak down test. Motor is all original except for they updated thermostats and plugs and water pump have been changed every year and ran with Dons cocktail every tank. Motor still runs great but had a slight occasional miss at idle things the reeds may be chipped if that helps anyone.

When i bought the boat in 2011 it had 234 hrs and comp numbers were
1-92 2-91 3-97 4-101 5-88 6-93

The dealer now is saying i need a new powerhead and quoted me 7000 bucks for it. I have no idea on how much a new powerhead should cost to do

Thanks in advance. I am looking at trading or selling to get a newer boat.

[Ben Danbleume]

You've got better compression than when you bought it and they only vary by 15. I'm waiting to hear from the experts.

[ChrisCarsonMarine]

Do a proper carbon treatment and retest compression,it's barely out of allowable limits and it's worth a try to see if it will even out.500 hours is not at all high time for this model,If it does need a rebuild we can take care of it,and yes it's very likely you will find chipped reeds,we make reeds for optimax motors that safeguard the motor and improve performance,Chris

[B A Texan]

I am not sure how the dealer did the test but i would hope that they did the correct procedure. I will put new plugs in and run it good with quickleen and retest it myself and see what the results are. Could a chipped reed cause lower compression.

[billnorman1]

There is optimum compression and there is maximum variable allowance. On 4 stroke automobiles 10% is allowable. With one cylinder at 115, that equates to 15psi. The one at 95 is outside that, the lowest should be 103.5 psi, 115-11.5=103.5.
HOWEVER one should ensure the compression gauge was calibrated and the test was properly done. I'd recommend you buy a new compression gauge, Harbor Fright has them, and do it yourself. There's a lot of money on the line.

[06 SB]

Do a good, thorough carbon treatment as Chris mentioned. Retest and go from there. In any case, get those steel reeds out and replace with fiber reeds. TDR or Chris's...both are good, you decide.

[EuropeanAM]

You've got better compression than when you bought it and they only vary by 15. I'm waiting to hear from the experts.

Well actually... that's a 20 psi variance (which is not acceptable). 115 - 95 = 20.

I agree that a good decarb and running some QUICKLEEN through the engine, then repeating the compression test would be wise.

Do not be surprised with readings that are right at the max variance on this particular powerhead series. #3 and #4 tend to come in at or above the top of the manual specifications (and this is very consistent, even on freshly broken-in factory powerheads).

Specs: 90-110 psi, Max Variance of 15 psi.

I would not even think about a rebuild until treated with Power Tune and run with at least 1 tank containing Quickleen and Quickare. See the FAQ for other recommendations to help combat carbon.

[tomloans]

Well actually... that's a 20 psi variance (which is not acceptable). 115 - 95 = 20.

I agree that a good decarb and running some QUICKLEEN through the engine, then repeating the compression test would be wise.

Do not be surprised with readings that are right at the max variance on this particular powerhead series. #3 and #4 tend to come in at or above the top of the manual specifications (and this is very consistent, even on freshly broken-in factory powerheads).

Specs: 90-110 psi, Max Variance of 15 psi.

I would not even think about a rebuild until treated with Power Tune and run with at least 1 tank containing Quickleen and Quickare. See the FAQ for other recommendations to help combat carbon.

Don i would like to run power tune and quickleen and Quickcare through the engine for a one thorough cleaning. What is the recommendation amount to put in the tank per gallon? I could not find it in FAQ Here is what I found only... Please let me know Don...

Fuel Additive Recommendations:
-Stabilize fuel ANYTIME fuel will not be consumed and replaced within 15 days!!!
-Optis (ALL, including XS & ProXS): Quickleen in EVERY TANK OF FUEL. You CAN combine Mercury QuickCare or QuickStor Fuel System Treatment & Stabilizer with Quickleen. Use the recommended "dose" of each product per the bottle instructions. For anyone questioning Quickleen recommendation- see Service Bulletin 2001-12 (yes, it's been recommended since 2001!!!).
-Quickleen may be used in ANY Mercury engine- it helps to prevent/remove carbon buildup (primary purpose).

------------------------------------------------------------------------------------------
"Mercury Component Cocktail"- for EVERY tank of fuel, whether or not your fuel contains Ethanol: (Chemically, this works much the same as the previously recommended (and now to avoid alcohol content) cocktail, and requires less components.) This is Don's Preferred "Cocktail":

-1oz Mercury QuickCare +
-1oz Mercury QuickLeen
----------------------------
Per 5 Gallons of Fuel (in EVERY TANK).

In addition to the above, it is acceptable to add 150:1 mix of Premium PLUS in the fuel tank (for OPTIMAX engine models). This has been proven to benefit fuel system components by providing additional lubrication ONLY to the fuel system components (especially the direct injectors- which are often left DRY after engine shutdown).

(If leaving fuel in boat for more than 30 days, be sure to also add Mercury QuickStor).

[EuropeanAM]

Please remember- One engine (only) per post to avoid confusion and/or post hi-jacking. The below information will be helpful to both of you, I believe.



Power Tune should be used as follows:

-Bring engine up to operating temperature

-Remove ALL spark plugs

-Spray power tune into spark plug openings liberally (it is a foamy consistency).

-Reinstall spark plugs

-Tilt engine UP fully and allow it to sit overnight.

-Start engine and allow it to reach operating temperature

-Run engine for at least 5 minutes, on the water, in FWD gear at 3500-4500 RPM's.

-Repeat above at least once.


** I would recommend using all of the components listed for the "Cocktail", including the 150:1 premix of Premium Plus Oil

Also... make sure you are running DFI Oil (and if there is an improvement in compression- you might consider switching to Racing Oil for a few tanks).

You've got a PM.

[B A Texan]

Thank you very much for the info.

Would adding extra quickleen for the first tank of fuel help clean it out better or should i just stick to the recommended amount like I have been doing. The only part of the cocktail i have not done is the premium plus part but i will start when i fill the tank next time. I have been running DFI oil as long as i have had the motor. Would racing oil still help.

What ever i can do to not have to rebuild the motor and feel comfortable selling it to someone knowing i am not selling a time bomb.

[Macsimus]

Please remember- One engine (only) per post to avoid confusion and/or post hi-jacking. The below information will be helpful to both of you, I believe.



Power Tune should be used as follows:

-Bring engine up to operating temperature

-Remove ALL spark plugs

-Spray power tune into spark plug openings liberally (it is a foamy consistency).

-Reinstall spark plugs

-Tilt engine UP fully and allow it to sit overnight.

-Start engine and allow it to reach operating temperature

-Run engine for at least 5 minutes, on the water, in FWD gear at 3500-4500 RPM's.

-Repeat above at least once.


** I would recommend using all of the components listed for the "Cocktail", including the 150:1 premix of Premium Plus Oil

Also... make sure you are running DFI Oil (and if there is an improvement in compression- you might consider switching to Racing Oil for a few tanks).

You've got a PM.

Really appreciate the outline for the Power Tune procedure. But, curious about the racing oil recommendation?

[EuropeanAM]

Mercury Racing Oil was formulated for the Military to be used in engines where fuel quality was always in question (as well as in some multi-fuel engines). It's cleaning properties are very impressive. It is, however, very expensive.

[coachallen]

Watching

[rakkc]

Mercury Racing Oil was formulated for the Military to be used in engines where fuel quality was always in question (as well as in some multi-fuel engines). It's cleaning properties are very impressive. It is, however, very expensive.

Whats the requirement to switch from DFI to the Racing Oil? Anything in particular or Can you just fill up the oil tank? any issues with mixing of the 2 oils? Thanks

[Savage]

Whats the requirement to switch from DFI to the Racing Oil? Anything in particular or Can you just fill up the oil tank? any issues with mixing of the 2 oils? Thanks

Tanks must be drained completely. The two oils can NOT be mixed.

[Jtreed99]

Is there some type of negative interaction between the oils? It would seem if that were the case a full line flush and purge would also be required? Especially areas oil pools like the bottom of the compressor?

[EuropeanAM]

According to Mercury- the Remote oil tank should be emptied/cleaned, confirm the strainer is clean, and then refill the remote tank with the new oil.

The engine-mounted tank should be fine, as that oil is turned over pretty quickly.

My understanding is that the two oils simply do not mix well in larger quantities (but we were told that the engine-mounted tank's volume would not be a problem). I have a dozen or so customers that have made the switch successfully, following this method.

[B A Texan]

I did the power tune treatment 2 times and when i got back to the ramp the second time i did the compression test as described on here and my numbers are as follows
1-86 2-88 3-93 4-96 5-87 6-89. This is using a compression tester off of <unmentionable> which i feel that the gauge is a cheap gauge. All numbers were tested 2x and came out the same. As far as variance across cylinders i feel that it is good. Please let me know if there is something i should be worried about. thank you

[EuropeanAM]

Likely the gauge- the variance is well within specs, and even with the suspect gauge your lowest cylinder is just 4 psi below the minimum.

Given the age of the engine- I would keep it on a good diet of Quickare, Quickleen and DFI oil, along with plenty of runtime in the 3500-4800 RPM range and run it.

[B A Texan]

Thank You very much for the wealth of knowledge you provide. I will make sure to keep the quickleen and quickare in every tank and be sure to run it every trip to try and keep motor as clean as possible. Would power tune be a wise yearly maintenance routine to keep the motor healthy for as long as possible.