engine repair costs

[Jim Teasdale]

I recently read a forum post suggesting mercruiser engines need repair work every 2,000 hours. Are these repairs a rebuilding of the engine or something else? Does anyone know what the ball park expense of rebuilding a mercruiser engine? Your willingness to share information is very helpful. Thanks in advance.

[SPOONFEEDER]

I just had my 454 mercruiser totally rebuilt 2 years ago, cost me about $4000 all said and done. Not sure where you got the 2000 hr number. Mine did have 3000 on it, but I know guys that have over 4000 hrs on them and running good. Need to take care of them properly.

[Jim Teasdale]

Thanks Capt. Larry. I'm not knowledgeable about these engines (or engines in general) and I read about the numbers I posted on a fishing site I have not been able to locate again. The info I have received on walleye forum has been to the best of my knowledge - excellent. Do you think - as a general rule - the hours on the engine are more significant than the age of the engine - is a 1990 with 1800 hours in better condition than a 1995 with 2100 hours?

[skipper9]

4000 to 5000 hours are common. It really just depends on the way it was used and serviced. Larry is right you should be able to replace the long block for around $4000.

[Jim Teasdale]

Thank you, Kent, branhamautomotive, cooleyfarms, Tom, and Wakina.

[pimplepounder]

I recently read a forum post suggesting mercruiser engines need repair work every 2,000 hours. Are these repairs a rebuilding of the engine or something else? Does anyone know what the ball park expense of rebuilding a mercruiser engine? Your willingness to share information is very helpful. Thanks in advance.

Hello Jim,

I am, a life long mechanic. I have worked in the diesel, ag, automotive , and marine industries. I am now a professor at UNOH in Ohio. There are a few situations over the years that have been engineering flaws, but more over, it all falls back to a few things. Clean oil, clean air, oil pressure, and temperature. As long as all of these things have been maintained the engine should keep running like a champ.

One of the easiest indicators of engine wear is finding oil in the air breather. This could indicate excessive piston ring blowby. Being over filled with oil could also cause the same problem, or operating in very rough conditions. Your crankcase ventilation system is one thing that gets overlooked often. Engines are designed to pull in filtered air into the crankcase and draw out the crankcase vapor to be re-burnt in the inlet filtration or PVC system. If either side get blocked though, it cannot work. The crankcase can build pressure cause excessive leaks and contaminate the engine oil.

In short, check your intake air breather if it is clean great, if it has oil, check your venting system. and oil level. Another thing you can do is see if you have a lot of vapor coming out of the oil fill or dipstick tube while the engine is running. If you have what seems like a lot of smoky pressure coming out: it is not a desirable condition. ( Note) some injected engines may not run properly with oil cap removed.


Inboard and Outboard, 4 strokes are not much different... 2 strokes are


My 2 cents,, Kent

[pimplepounder]

I recently read a forum post suggesting mercruiser engines need repair work every 2,000 hours. Are these repairs a rebuilding of the engine or something else? Does anyone know what the ball park expense of rebuilding a mercruiser engine? Your willingness to share information is very helpful. Thanks in advance.

Hello Jim,

I am, a life long mechanic. I have worked in the diesel, ag, automotive , and marine industries. I am now a professor at UNOH in Ohio. There are a few situations over the years that have been engineering flaws, but more over, it all falls back to a few things. Clean oil, clean air, oil pressure, and temperature. As long as all of these things have been maintained the engine should keep running like a champ.

One of the easiest indicators of engine wear is finding oil in the air breather. This could indicate excessive piston ring blowby. Being over filled with oil could also cause the same problem, or operating in very rough conditions. Your crankcase ventilation system is one thing that gets overlooked often. Engines are designed to pull in filtered air into the crankcase and draw out the crankcase vapor to be re-burnt. it the inlet filtration or PVC system. If either side get blocked though it cannot work. The crankcase can build pressure cause excessive leaks and contaminate the engine oil.

In short, check your breather if it is clean great, if it has oil, check your venting system. and oil level. Another thing you can do is see if you have a lot of vapor coming out of the oil fill or dipstick tube while the engine is running. If you have what seems like a lot of smoky pressure coming out: it is not a desirable condition. ( Note) some injected engines may not run properly with oil cap removed.


Inboard and Outboard, 4 strokes are not much different... 2 strokes are


My 2 cents,, Kent

[branhamautomotive]

As a full time auto tech I will agree with everything said so far. With proper maintenance engine can run many thousands of hours. There us no cut and dry way like hrs to tell if a motor needs rebuilt. But there are a few basic and easy check with tools that don't cost much or are rentable through the local parts store.

One i like to start with that gets overlooked alot is a simple vaccum reading. Given the overlap in the cam grind of most marine motors reading around the 13 area are not uncommon. The more the overlap in the cam the less and more erratic that number becomes. But you want to see a fairly steady reading, you don't want to see very very rapid jerking or bouncing of the needle.

Do a compression and cylinder leak down or balance test. On the compression you are looking for even readings would guess 150 psi plus seeing the hrs you have. I like the leakage test better, over 20% is bad, seeing you ours 10 to low teens would be normal.

As far as bottom end we only have oil pressure and I have seen motor with 50 psi knock and motors with 10 psi run perfect. You can cut open your old oil filter check for fine metal powder, thst would indicate an issue

Motors can go bad at any time I have seem them with less than 100 burn up. Keep in mind there are hundreds of moving parts often times with 2 or 3 thousandths of inch of clearance and a small film of oil, running at 3000 plus rpms sometimes hours at a time. And these are built by a company that is looking to save a penny at any chance they can.

[cooleyfarms]

We relate engine hours to auto mileage using every hour as equivalent to 50 miles (50mph). 100 hours would be 5000 auto miles, time to change oil & filter. 1000 hours would be 50,000 miles and 2000 hours would be 100,000 miles. These are mileages (hrs) when auto manufacturers suggest more extensive maintenance. We have farm tractor engines with over 8000 hrs still running fine and using no or very little oil. Keep in mind these are industrial engines and we strictly follow manufacturers suggested maintenance schedules. Check your dipstick before starting for use that day and note any usage over time. Usage of more than a quart at 100 hrs would indicate a mechanic should be consulted. (In my experience)

[pimplepounder]

I agree with cooleyfarms input on oil consumption. A little oil must get past components for lubrication, but today's engines are very efficient mainly due to tight tolerances. Excessive oil consumption between recommended oil change intervals indicates engine wear. There are tests that can determine where this may be happening. I would also consider 1 quart or less consumption within 100 hrs, to be normal. In Ag and marine equipment this is mainly WOT Rpm and this is a lot of hours in reality, at this engine speed. To use a quart or less is pretty darn impressive when you think of what all is really happening inside..

Little things like this can tell you a lot.