Possible issue with the 340.... Help!

[Steve S]

Ok. Here I am on the road to attend the survey in the morning. I just got a call from the broker. I had the local Sea Ray dealer do a compression check on the engines today.

7.4L Horizons 380HP

Port was good. All cylinders 150-160lbs.
Starboard was similar except for one cylinder at 120lbs.

Thoughts? Is this a deal breaker? Should I walk or not?

Or have it rechecked tomorrow after the survey and sea trial? The boat hasn't been getting much use lately. Has 550 hours on it (2000 model). Maybe it could be crud on the valve. I had that happen to me one time with my Bonanza. After a good high power flight it then tested much higher.

Opinions?

Thanks!


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[hottoddie]

I would not walk. Seen that before. I would run the boat for 1-2 hours and retest. My bet is it will be OK. If not negotiate 3-4 k off the price for a top end valve job.

 

[moparlvr4406]

Agreed..
Run it for a while then retest .. if it still has a low cylinder have the wet test that one or do a cylinder leakdown test to determine if its a valve or rings.

 

[moparlvr4406]

Oh yeah...
And don't buy a broken boat.would the 3-4k off the price be worth not getting to use it this summer??

 

[Jetmart]

Ok. Here I am on the road to attend the survey in the morning. I just got a call from the broker. I had the local Sea Ray dealer do a compression check on the engines today.

7.4L Horizons 380HP

Port was good. All cylinders 150-160lbs.
Starboard was similar except for one cylinder at 120lbs.

Thoughts? Is this a deal breaker? Should I walk or not?

Or have it rechecked tomorrow after the survey and sea trial? The boat hasn't been getting much use lately. Has 550 hours on it (2000 model). Maybe it could be crud on the valve. I had that happen to me one time with my Bonanza. After a good high power flight it then tested much higher.

Opinions?

Thanks!


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See Mike Bush's Article on Compression tests. You mentioned a Bonanza.

http://www.sportaviationonline.org/sportaviation/july_2013#pg36

 

[Bob & Sue]

See Mike Bush's Article on Compression tests. You mentioned a Bonanza.

http://www.sportaviationonline.org/sportaviation/july_2013#pg36

Thanks for the post, that's a really interesting article I know of several folks that bore scope their drag racing motors but had no idea of how far the technology had come the next time they a do scope I want to watch them. This could really make a difference in a boat survey knowing what's wrong.

 

[Steve S]

Thanks Jetmart! My Bonanza mechanic was an old time Bonanza owner and is now into turbine repair so he did borescope my Bonanza. It got the green light and all was good next annual. I also used to follow Mike Busch's articles all the time before I sold my bird...

That's why I was thinking I should go with the survey and sea trial and recheck it after a good run... I just have no experience with the 7.4 Horizons so I wanted to ask...

And if anyone is around Old Hickory Lake tomorrow..... And wants to stop by and take a look at the 340... PM me...


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[Larry]

That is definatly not deal breaker numbers, I would bet it is one of the center two cylinders that has the lower compression, this is probably caused by a leaking exhaust gasket. Remember these particular Horizon motors were notorious for water intrusion if it didn't have the exhaust update, originally they had the "log" style muffler, but the update should include the 3 inch spacer on the risers and converted to the "lift" style muffler. The problem with the old design would be especially when you shut the motor down, due to the valve overlap there would be a vacuum created by the engine and water sitting in the log muffler could be sucked back into the engine.
Don't get me wrong, these are great motors, but I would run away from one without the updates.

 

[Steve S]

Larry,

I agree with your assessment of "run away" with out the mods. That was one of the first things I checked and they do have the riser blocks so I think the mods have been completed. I am not sure of the difference between the log and lift mufflers but I will be discussing it with my surveyor today.


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[Carver370]

Run the boat and recheck. I've seen this a lot.

 

[Steve S]

Starboard engine is o

Port
1-160. 2-160
3-160. 4-145
5-120. 6-140
7-160. 8-135

So most of the one side is out of spec. Owner is saying he has to fix what is wrong.

Discussing where to have it fixed. It has been suggested that I do it at home so I have the warranty back at home. However then what happens if we find out more is wrong?

Thoughts?



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[moparlvr4406]

I had some repairs done on my 340 before shipping but with an agreement with the SR dealer that did the repairs
if something was wrong in materials or workmanship within their warranty period (90 days) reimbursement would be made within 15 days of invoicing from a licenced marine repair shop....no issues so far.

 

[Steve S]

Turns out according to Mercruiser a 30% spread is acceptable with no cylinder to be below 100.




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[moparlvr4406]

I wouldn't accept anything over 15% variance ...that has been the standard on a V8 engine since the beginning of time
just off subject FYI....on Ford cars they said 1 quart of oil consumton in 900 miles was acceptable....on a brand new car

 

[timemachine]

My 2006 340 may be going on the market if you want some info?

 

[MarkNewbie]

Heck, mine is on the market right now.