Engine hours

[MikeyP]

I would like to know if anyone has any knowledge about the maximum hours on a straight inboard engine before thinking about replacement? I understand a lot would depend on the proper maintenance done on the engine before reaching those hours. Let's say a boat that was really taken care of has around 4000 engine hours. Would we be looking at possibly needing an engine replacement soon? I know this might be hard to predict, but I'm sure some of the experts on this forum could venture a good opinion based on their experience. Thanks for any knowledgeable replies.

Edited July 9, 2014 by MikeyP

[troubles]

4000 yep soon. Lets see what the guys who have changed engines say!

[Diversion]

What type of engine, small block or big block, MerCruiser or Crusader? Lots of variables to consider. A compression check would also help to shed light on the engine's health and how much life it has left.

[Fish Hunter]

I know of a mid-late 80's Sportcraft with almost 7000 hrs on it. 

It was bought new, oil has been changed like clockwork at 50 hrs, every time, and never abused.

Runs great to this day.

[Sea-IV]

I would advise to just get a compression test and compare the results to the parameters of your specific motor. Look for leak down meaning see if each cylinder holds compression. Cheapest way to see what your motor is doing condition wise.

[Fish Hunter]

Yep, a leakdown will tell if it is getting past either the intake,(air coming out the carb) or exhaust valves,(air coming out the exhaust system) or the rings.(air passing out the crankcase breather).

Certainly would not expect all equal, or probably not within 10%, but it is not a Nascar, or 1/4 mile maximum effort application either, where 0% leak is needed.

[Sea-IV]

I agree with that. Any engine with 4000 hours is bound to have some blow by but if its excessive it might be time for an overhaul not so much a replacement, although these days its just as affordable but I like using the original block cause replacements don't always fit the same. Just rebuilt a Volvo inline 4 for a friend that had about 4000 hours on it and putting back was very easy.

[MikeyP]

I agree with that. Any engine with 4000 hours is bound to have some blow by but if its excessive it might be time for an overhaul not so much a replacement, although these days its just as affordable but I like using the original block cause replacements don't always fit the same. Just rebuilt a Volvo inline 4 for a friend that had about 4000 hours on it and putting back was very easy.

 

I agree with that. Any engine with 4000 hours is bound to have some blow by but if its excessive it might be time for an overhaul not so much a replacement, although these days its just as affordable but I like using the original block cause replacements don't always fit the same. Just rebuilt a Volvo inline 4 for a friend that had about 4000 hours on it and putting back was very easy.

 

Any idea of the cost of overhauling twin 5.7 liter mercruisers?

[Sea-IV]

Any idea of the cost of overhauling twin 5.7 liter mercruisers?

I would guess if the cylinders just needed a good honing with replacing everything(rings,bearings,cam and seals) it could be about $1500 for the parts and then what ever the labor rate at the shop is. 5.7 a common motors, the cost by time all is said and done it might be better to replace them with a remanufactured motor. A guy I just met just paid $5300 for a remanufactured 5.7 with a 3 year warranty and he did the work himself. It depends on your budget.

[lakebound88]

I paid 1500$ for my reman motor and did the work myself.. To each their own. Just be sure to do it nice not twice . .

Sent from my XT907 using Lake Ontario United mobile app

[Fish Hunter]

Any idea of the cost of overhauling twin 5.7 liter mercruisers?

Dig deep, and grab a heap.

[G-Daddy]

Replaced the 350 Mag at 2000 hours due to water problems.  I was told by the Mercruiser dealer that I got the last available factory new inboard 350 Mag without catalytic converters.  It has a tag on it that says not for use in boats in the US except for repowers.