High Engine Hours

"Hello All, Real Rookie here.

"Hello All, Real Rookie here. I've been boat shopping for a few months now. I've found a Sea Ray that was owned since new by a Sea Ray employee. According to seller, the boat has been meticulously maintained by her employer (it's the cleanest I've seen). But the engine has about 400 hours on it (2001 5.7 Merc, carb). With most of those hours being in salt/brakish water, is it possible for the motor to be in really good shape, or do they pretty much die after a few years even with good maintenance habits (that's what I've been lead to believe). I've heard salt takes it's toll regardless of how you try to prevent it.

Thanks for any insight.

Jim."

I just bought a 78 searay from

I just bought a 78 searay from a guy who owned it for the last 20 years and kept it up.(twin 5.7 carbs) it has 1200+ hours on each engine. It is one of the best running boats i have owned so far.

"Wow, Thanks Jeff. I've b

"Wow, Thanks Jeff. I've been told that the manifold (and another part, the name escapes me, but it's where water flows through for cooling) get eaten up with corrosion if you run the boat in salt water. The source said that it makes only a little difference if you flush the engine after use, it's going to corrode either way since it's cast iron.

I've seen boats only two or three years old that have engines rebuilt. I wonder, "What in Sam Hell have they been doing with that boat to trash an engine in 2-3 years"?

What are your thoughts on this?

Thanks a ton,,,,really.

Jim."

"lifetime of saltwater manifol

"lifetime of saltwater manifolds, and elbows (a.k.a. risers) is 7-10 years max. we have all heard about the guy down the dock who had a set last 20 yrs. He's an idiot. I replace a lot of otherwise perfectly good engines due to this. keep this in mind. any other parts in contact with salt will have shortened lifespans as well. 400 hrs. is not nearly used up if maintained. compression, and oil pressure will tell a lot about internal wear. good luck. S."

"Jim

Its not the hours its

"Jim

Its not the hours its the maintenance. I have a Merc 454 in a 30 ft work boat with 5100hrs. In my experiance it still sounds as strong as the day it was born. Oil changes, tuneups, all money really well spent."

1. (manifolds and risers&#

1. (manifolds and risers) they say you should replace them at 2-5 years depending on use. after five years you a pushing your luck. they rust from the inside out and if they fail your engine ingests water through the exhaust. not good. new manifolds and riseres run about $500 per engine and if you can change your own oil you can probly change them. also they have a date cast into them (11/06 this format) on the month they were made so you can get an idea of how old the are.
2. if i use my boat keep the engines at 3000rmp and do the maintenance on time and my friend runs his wide open throttle all the time and never changes the oil in two-three years I would say he would be having engine trouble and i would be out fishing.

"All good information guys, th

"All good information guys, thanks a ton. One last question though: Since they corrode from the inside out, how do you tell if they are at a stage that needs changing? OP and compression as Scott states? I'm fairly mechanically adept, and could probably do the work, but I don't want to do it prematurly/unnecessarily, or wait until my engine cooks. Are there decent engine manuals out there?

Thanks, Jim."

"Put a set of stainless steel

"Put a set of stainless steel manifolds on her. They're not cheap, but last forever. The other benefit is the riser and manifold water jackets are not directly connected like cast iron. They use a connecter hose. It's impossible for them to leak at the riser/manifold connection!"

"..."Since they corrode fr

"..."Since they corrode from the inside out, how do you tell if they are at a stage that needs changing?"

Strange that you mentioned that! I just wrote an article for the 'Mariner' magazine that addresses that very issue.

If you suspect water is getting in, try the hammer test. Take a ball peen hamme and gently tap away on the manifold. Go over every square inch of it and listen intently. Good metal rings like a bell; rusted, thin metal has a dull thud to it.

One indicator of possible trouble can be heard when starting the engine. If it goes R-R-R-R--hesitate-R-R-R--hesitate--R-R-R instead of a nice, smooth R-R-R-R-R-R-R-R, that's an indication of water in a cylinder (that resists being compressed. The best way to test this is to pull the coil wire and crank it after an overnight sit (and a good run the day before).

Jeff"