04 yamaha 4 stroke vibrate stalls at idle

[rudderz71]

So just got the problem diagnosed
blown head gasket!! I have put 2 hours on the engine since the oil change and spark plug work was completed. If you recall the wires were crossed by the mechanic . Motor ran perfect when stored. I guess the battle will begin on payment. Said the number (2) cylinder had a lot of oil in it. Said it could happen from trimming the engine up? Not sure where to go at this point
what does this cost on average, and should i go after him?

[Nautical]

Cant go after him, you cannot prove he crossed the wires or did anything incorrectly. You found the crossed wires and corrected that and did the plugs.

[99yam40]

4 strokes will have a tendency to have oil seep by rings if tilted up before all the oil on back side of rings is not allowed to drain back into the crankcase before tilting up.
usually causing smoking at start up.
I would not think it would be just one cylinder though and do not see how swapping plug wires would blow a head gasket.

Heat can warp a head and blow gaskets

[rudderz71]

he found the spark plugs to be crossed, not me. gave me the boat back after putting them back together correctly, only to find out that the 3 spark plugs on the port block were all fouled. I did run the boat to try and troubleshoot the issue so that is on me. SUCKS! I put about 2 hours on the boat since this disaster. Do you suspect and more issues could have happened. A warped head? He did say something about the trim of the engine and oil being dumped in or something. 900 hrs and a head gasket blown. should i be worried or is this a pretty standard procedure. Only had 30psi on that cylinder after leak down test was done and compression.

[99yam40]

he found the spark plugs to be crossed, not me. gave me the boat back after putting them back together correctly, only to find out that the 3 spark plugs on the port block were all fouled. I did run the boat to try and troubleshoot the issue so that is on me. SUCKS! I put about 2 hours on the boat since this disaster. Do you suspect and more issues could have happened. A warped head? He did say something about the trim of the engine and oil being dumped in or something. 900 hrs and a head gasket blown. should i be worried or is this a pretty standard procedure. Only had 30psi on that cylinder after leak down test was done and compression.

Compression is even on all cylinders, and the pressure at the rail is where it should be.

I do not understand,
you said compression is good, but now you say it is not

I replaced the spark plugs on the port side of the block cylinders 2, 4, 6 and put the wires back the way they belong.

and now you say he found the plugs crossed and fixed it back correctly?

Somethings are not adding up with what you post


I have not had a head gasket just pop without something causing it, but that does not mean it cannot happen I guess.
Is he sure it is a head gasket and not a valve problem with only #2 involved?
I did mention a valves not sealing in one of my responses.
A leak down will show where the cylinder is leaking to if done by someone with the proper training

As luck would have it the next post I read had info for you on leak down testing
http://www.yamahaoutboardparts.com/f...tml#post106636

[rodbolt17]

no way no how any head gasket failure will allow oil into the combustion chamber.

however we do see the occasional head failure where corrosion eats a track under the gasket and allows water into the cyl.

ya always gotta think, if you wish to diagnose and repair you MUST know how the system works and what is missing when it doesn't work.
customers like what your describing is the ones I send down the road.

its not always the mechanics fault,although sometimes it is, but don't instantly blame the last guy that had the hood off.

when ya get to the shop.
look on the wall.
look for YAMAHA school certificates.
better yet find a shop that employs a Yamaha MASTER tech.
that cert will be on the wall as well.

[rudderz71]

I agree 100% just hope this repair goes well and I can put this behind us. Not real sure about the oil but once I get the ins and outs of the exact issue to blow the gasket I will reply back. I am also blaming myself as well for running the boat for an hour or 2 after knowing there was a problem (not knowing the wires were crossed). By the way the compression data was from the mechanic not me. He first told me the compression was good, then followed by telling me the number 2 cylinder was at 30 psi. I was just relaying info to you guys to get another opinion. Thanks for the replies. I will post results once the engine gets buttoned back up. I just got pissy when the mechanic accused me of crossing the wires. Not right for sure. I paid him 800 dollars to service the engines why in Gods name would i tamper after that. I assumed the boat was ready to roll. Oh well life lesson learned. Thanks Again!

[rodbolt17]

like I said.
LOOK ON THE FREAKING WALL.

trust me, I have done this type of work since about 1976. lots of changes but the MECHANICAL parts are the same since the 1800's.

only difference is the fuel and ign controls got a bit different.

heck I ran across my DWELL meter the other day, I aint used it in at least 15 years.

[99yam40]

Did this guy do a leak down test to see where the cylinder was leaking to?


Rod got me to thinking and I am not sure what happened the the dwell meters I had back 40 or so years ago
Still have a few of the hand tools, compression gauge, and Snap on timing light from back then.
Having sons kind of made things disappear some over time

[boscoe99]

like I said.
LOOK ON THE FREAKING WALL.

trust me, I have done this type of work since about 1976. lots of changes but the MECHANICAL parts are the same since the 1800's.

only difference is the fuel and ign controls got a bit different.

heck I ran across my DWELL meter the other day, I aint used it in at least 15 years.

Let's not dwell on the past.

[rudderz71]

UPDATE

Gasket was installed and engine was buttoned back up. According to mechanic everything looked beautiful cylinder walls etc. Problem remaining is still no idle. Said he swapped some senors from starboard engine with no luck? ANy ideas???

[rudderz71]

cylinder still at 30psi

[99yam40]

Did this guy do a leak down test to see where the cylinder was leaking to?

again see if you can answer my question

[TownsendsFJR1300]

+100 ^^^

A leakdown test with compression that low, should be VERY obvious.

It doesn't sound like a leakdown test was EVER DONE, just a compression test..


Just mixing those wires up would have me running from this shop...


I'd be looking for certified yamaha mechanic.

[rudderz71]

Guy claimed to do a leak down test so he said
If he did I guess i won't know
You guys think the power head is toast at this point ?
He claims the cylinders looked great
Yamaha rep is coming next week