engine questions

[searay30]

I have had my sea ray 30 sedan bridge since the spring of 2002. The starboard 5.7 merc was replaced at 350 hours, sucked up a bag and it over heated. the port is original with about 1025 hours on her. My normal cruising area is upstate new York, on the nys barge canals. I have made many trips out onto lake Erie, lake Ontario and the 1000's island and down the Hudson. But the majority of my hours been at canal speed 2000 to 2500 rpms. When I was cruising in open water I held it to about 3200 rpms

Two years ago I took to a mechanic for a tune up. He consider the port engine a "little tired" because one of the cylinders were running down about 8 pds. He said not to run it hard. I have since run the port engine under 2800 rpms and the starboard at 3200 rpms

Its been about 2 years now and I put an additional 25 hours on both of them. So my question are there any additional outward signs that their might be some engine issues occurring, such as low rpms, temps, steaming, burning up or leaking oil or running rough?

thanks in advance,

rob ( she wasn't a classic when I bought her but she is now)

rob2102@aol.com

 

[hottoddie]

What are the WOT rpms for both engines? What year are they? 1025 hours is not a lot of hours on a marine engine. If you mean one cylinder is 8lbs low from a compression test that is not much and if both engines turn up to the rated rpms around 4400 then they are both healthy and run them the same. Marine engines rarely wear out, they usually die from poor maintenance and water ingestion.

 

[searay30]

the port engine about 4000 the starboard turns about 4300. The port is original to the boat, a 1989 5.7. The starboard was replace when she had 350 hours on it in 2003,so the new engine has about 700 hours on it. When do marine engines need to be rebuilt?

 

[hottoddie]

If the port engine does not consume oil or leak oil I would consider doing a top end overhaul. That is unless you want to go all in and replace it as well. Are these raw water or fresh water cooled engines? If raw water cooled I would lean toward replacement same as the starboard.

 

[searay30]

runs the same as the the starboard, no leaks or above average oil use. The starboard was replaced in 2003 when it sucked up a plastic bag and overheated. You think the port engine is a time bomb?

 

[hottoddie]

I think the port engine would be fine with a top end overhaul along with a complete tune up. Make sure the throttle linkage in advancing the carb linkage all the way. I would not run the engines at different rpms.

 

[nickdcj7]

i would start with the tune-up and maybe a carb rebuild (if it has a carb) and clean the flame arrestor. 8psi low is not that big a deal on one cylinder. I personally wouldn't jump into a top end rebuild until everything else is good and you still found it down on power.