What do you make of this low compression in 2 of the engine cyclinders..........

[rwadlow]

After screwing around with my boat for 2 weeks they come up with this (mind you they only found this because of the so called Trade Check)
Boat has been running strong all season (2002 Supra Launch 22ft SSV) starts up every time never ever a problem with the motor or temp gauge

I had a knocking sound so we took it to this new dealer mainly deals w/ Malibus and they said it was just a Coupling on the Prop Shaft doing the tick tick tick sound (motor ran great in neautral no problems etc)

I kind of liked this 2008 malibu wakesetter so I said yeah do a trade check

* They said yeah your engine is running rich need to test the diagnostic codes, then they say I have 35 in cyclinder and 65 compression in the other (all other six cyclinders are running great) Could be a blown head gasket but not sure ? They would not know for sure until it has been changed

My question would we of known if it was running bad on six cyclinders? Should we beleive this shop ? Should we just get the boat back and run it and see if we notice anything? let me know what u all think

NOTE we would of NEVER KNOWN any of this if it was not for this trade check *** hmmmm

[lively]

Sounds like someone is trying to make some money ... how many hours on the engine again ?
That low of compression you would be smoking a hot mess! Usually 100- 150 lbs is ideal ..
basically u need to get a coolant pressure test to check for blown seals, or u could drain the block and have them hook a smoke machine to it ...

All these test it put the engine under false pressure (load) and if there are any leaks or gaskets blown then it will go there to verify leak...

I mean a rebuilt long block is maybe 1k at most .. and if something is cracked or overly expensive like diag fees / labor / parts ...look into a rebuilt engine ..
Just my 2 cents ... I would ask a mom a pop shop rather than some dealer ... least u will get ur moneys worth

[sydneyACE]

You would think for sure that you would notice the engine not running right if a head gasket was blown that bad. (35psi is pretty damn low.) Some other issues that sometimes come-up with blown head gaskets include water in the oil (pull the dip-stick, it will be cloudy and look like chocolate milk) and combustion gas in the cooling system. There are a few good ways to check for these things before you spend a bunch on labor tearing-down an engine.

I just did a compression check and leak-down test on mine because of a cooling issue. It doesn't take too long. These are also regular automotive engine test that can be done by any mechanic. The reason I say that is because some places (usually marine dealerships) charge a "boat tax" on everything they do. You can probably find a cheaper labor-rate from an "automotive" mechanic.

You probably aren't anywhere near us (Montana) but my brother and I do mechanic work on the side and would be more than happy to check it out for you. I'm sure we could diagnose and fix it for WAY cheaper than the dealer is quoting you.

If that's not an option, just shop around. Make some calls and see who will give you a fair quote.

[rwadlow]

Boat has 690 hours on it .. called my mom in pop mechanic dude lives up the street from me.
He said get th boat and run it and see how it does. If we are still worried he said he will gladly do another compression test. He said the thing might run another 500 hours with no problems he said just run it and enjoy it and do not worry ! I like those kind of answers :) !!!

Wow note to self and others BEWARE of having a dealer do a trade check ... economy is tough now and they want to put you in a new boat !

[rwadlow]

I am in southeast Missouri or I take you up on that offer in Montana .. I think we will just run it and see how it does.
Then this fall /winter take it to my mechanic and let him do all the test if the gauges / motor does okay !

Never have problems starting or anything , and run great under a load with ballast and wakesurfing ..

[wotan2525]

Sounds like the dealer is trying to set you up for a low-ball trade offer. 690 hours is nothing and as long as you've maintained it properly, a head gasket should not be bad.

A leak-down test will tell you for sure without having to start taking things apart.

[Jetlink]

Sounds like the dealer employees mechanics who attended the Shady Tree Mechanic Institute. Either they are trying to set you up to bend you over a barrel or this is a case of the id10t issue. I would grab the boat like your mechanic said, run it, do the test and then offer to show these techs how to do a proper compression check if the numbers are indeed good and then ask them how they got such low numbers. Perhaps a call to the BBB might be in order as well, tough economy or not, that is not how you do business.

[86 century]

What are the rpm at wot if you have two weak cyl she could start and idle fine but would definitely be down on power.

[lively]

Well just by listening to the symptoms. I would worrie more on having enough beer and smoked ribs rather than a trade in ..
I my self worked for BMW of grapevine Texas and was a service tech, every ticket we got we wrote it up phat because we run flag rate pay
.. more hours on the ticket ... more money in are pocket ...

I would just put gas in her, wax, beer, ect.. and roll with it ... if the engine is still pulling hard enough to surf behind. Then u still got plenty of good time left ...
us TEXANS call that the " GOOD TIME METER" ... good luck !

[csleaver]

Do you know of a shop or mechanic you can trust? Perhaps someone that does your annual maintenance, repairs, winterization, or something like that? Have them check it out. If not, ask for a referral from a friend that owns a boat that has a good relationship with a reputable shop or mechanic. Fixing something using a blog or message board is like fixing something over the phone, it usually does not work out quite right. But you may get a good tip, direction, or at least know what to expect from an honest mechanic.

[lively]

I would drive around and find a well know auto shop .. Talk to a L1 certified tech (ASE) , the field they certify in are straight
Diagnostics , have him do a leak down test .. Just over all inspection of engine and drive train .. I work on elevators for a living but still carry my ASE certs for general rebuild and alignment .. All I can tell u is usually it's no a big dill as long as you are not using
Oil and the compression is maintained through all cylinders .. U will be fine .. I mean how about u upload a good video of the
Noises or issues that are concerning you

[cadunkle]

35 psi is just along for the ride and that alone should be very noticeable. That one likely isn't firing. 65 psi is barely doing anything, maybe intermittent miss. unless you're oblivious you would feel and hear this. Pick up a compressiont ester and test it yourself. Or let the boat idle and pull the wire from a good cylinder, note RPM drop and change in engine sound. Replace that one then pull from the bad ones and note RPM and sound change with each. For the 35 psi one if it's actually 35 psi it won't change RPM or sound of engine at all. 65 psi cyl will likely make a slight difference but much less than any of the good cyls.