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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.
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.
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?
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.
Hello Jim,Quote:
Originally Posted by Jim Teasdale
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
Hello Jim,Quote:
Originally Posted by Jim Teasdale
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
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.
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)
Maybe I can help you. My profession is engine rebuilding. I have a complete machine shop locally. That's all we do. We specialize in gas and heavy diesel of all kinds....Passenger car, industrial, off road, marine, etc. 419.350.5455
Tom
Jim
The vast majority of marine engines are based on either Ford or GM long block engines, the same blocks found in automotive applications. The Volvo, OMC(and their replacements), and Mercrusiers are mostly Gm Based engines. They are typically just a regular automotive block that has been what most identify as marinized. The main difference is the use of brass in the water jackets in areas such as soft plugs and a high efficiency oil pump. The upper engine is where there are major changes made to make the engines suitable for marine use. Heads(sometimes), camshafts, intake manifolds and fuel delivery systems are the main areas that are changed to produce the the needed HP and Torque for the marine engine and the electrical systems, mainly the starters and alternators as they have to be USCG approve for spark containment. Here is a site that I have used for three different engine replacements both new and re-manufactured, I have never had a problem with any of the engines that I have purchased there. Sometimes it is easier and more cost effective to replace than to repair.
http://www.michiganmotorz.com/
On Edit: I have seen engines go on as little as 200hrs and as much as 6000+hrs. As an owner you can only do so much to prolong the life of your boats engine! Following the recommended maintenance schedules and allowing for extra time to get to where you are going does wonders in the longevity of your engine, so many people run their boats a WOT, change oil and filters on an irregular basis and then wonder why they have engine problems after a few hundred hours of use.
Mass produced reman engines with a few year warranty are always attractive. I though prefer to have a good reputation machine shop build. It's nice to know and actually talk to the ppl doing the work. Plus they are again not u singing the lowest cost parts they can get ahold of. Not saying all are that way but to many a penny saved us a penny earned. But that being said spending a few extra bucks on good bolts and better pistons goes a long way in the way a motor last too. You can run the correct way, do all the proper maintenence but if built with substandard cheap parts from over seas benders problem will most likely be close behind.
If rebuilding, good arp bolts, not bottom dollar piston, quality oil pumps and bearingand rings and even switching to roller cam lifters adds some money to build, but if only doing once as compared to twice starta to figure in the extra 750 or so bucks is alot cheaper than another build a few years later.
Good quality machine work is just as important too. There is a big differance in a motor balanced to 2 to 3 grams as compared to 20 to 25 like some of these mass producers do
All very good points!
Had one rebuilt several years ago and after tearing down and the baking(cleaning) the shop found a crack in the block in a bad area, I ended up with the cost of the original tear down and the cleaning and still had the cost of another block on top of that plus magnifluxing the second block and the actual cost of parts and labor to assemble.
On the last engine I replaced it was hard to not to look at the cost of a brand new GM engine(long block) with roller cam and lifters manufactured by the GM Marine engine division which cost $2699.00 3 years ago, I also drove to the business and picked up myself so no shipping costs were incurred! I did the switching of the parts from my old engine to the new engine myself so there were no costs involved there except for new bolts for intake and flywheel.
That engine is still running strong! Then again I did not have the option to rebuild as a head and the block were both destroyed between the #3 and #5 cylinders. It had burnt (melted) a channel in both the head and the block.
Sometimes there is no choice but to replace. But it pays to way all the options outs for sure. It is always nice to save a few bucks by being able to fix things yourself or with friends. Plus the pride in knowing g you did it. There is no way to know what way is best, though sometimes the condition of the parts in hand dictate which way we go.
A good used motor is another way to save money, if you can find one. Over the last 15 years I have put hundreds in cars and only had small number less than 10 ever be bad when I put them in. So less than 1%.
But no need to do any if his motor still has good life in it. Cause no way around, reman, rebuilt, used it's a large bill to get it back up and going.
Jim if you have any questions about checking the condition of yours out just pm me and I will do what I can to help you check it out
My Mechanic. Recommends Wolfs Head oil. I have Chevy 454's and he believes 100% on Wolfs Head. FYI
Quote:
Originally Posted by branhamautomotive
Thank you, Kent, branhamautomotive, cooleyfarms, Tom, and Wakina.
I run royal purple in my race motor, I personally don't have any experience with wolf's head other than hearing nothing bad about it, I know some like Mobil 1, some Brad penn, on and on. I am sure they are all great, and will pass one form of test better than the others, the main key is no matters who's name is on it, make sure it's of good quality. There is some cheap junk oil out there, and even more important than the name on the bottle is make sure oil of some kind is in there, anything is better than none. Alot of ppl nevery pull that long skinny stick ever
I had my old 305 228 hp engine replaced at Michigan motorz with a 350 vortec 315 hp engine back in 07 and its still going strong. these are new marine engines and are worth the money over a rebuild job in most cases.
This touches on the next question I hear alot. Remain stk hp or go up. We have found in most cases that most boat owners feel their bost could use extra power. And if increasing the hp by reasonable levels, 50 to 75hp, AND IF driven the same speed and way, you will almost always see a drop in fuel usage cause the motor is not having to work as hard to get done.
Now that being said, when we have extra power we almost never drive it the same way, cause the boat will run an extra 5 or 6 mph and we normally use it if we have it.
But either way rebuild or reman the hp comes for very little money
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.
My thoughts here, with a due respect.
Power does not come free. To get more power the two laws of Thermo Dynamics are always smacking us around. Efficiency is perhaps the most high performance quest we can have. If we could get a 1-1 relationship this would be awesome , but we cannot. Almost any hp increase is going to cost more in fuel, driveabilty,or engine wear. The engine is working harder because there are increases in compression, temperature, and pressures, even if rpm is less.
My thought are: if you do not think you have enough power, you do not have enough engine. You can give a scrawney guy some steroids, or just hire an big guy. Which one is going to pop a cork first?
Some charter boats would have their eng's rebuild/gone thru around the 2500hr mark. Having multi charter boats, this helps spread out maintance/replacement instead of having more than one boat/yr down and costs involved. This also helped reduce chances of an engine failure while on a charter and having pissed off customers and having to be towed in. Just as insurance so to speak. Also this was on carburetor engines. Carb engines run ALOT richer than injected ( at some load points more than triple of an injected engine), the excess fuel gets past the rings, washing down the cyl block walls, dilutes the oil, which increases internal bearing, cam wear dramatically. Just compare average engine life on older carbureted engines vs todays tightly fuel controlled injected engines. Your spark plugs, dist. cap/rotor, appearance of the oil on your dipstick can tell quite a story. Along with oil pressure readings, vacuum gauge, engine performance etc.
Ditto's on everything ebijack said. When sequential fuel injection came about, the efficiency on engines went way up as did wera and tear. We have to reply a lot more on software and electronics, but this is how just about everything works today. I never thought about having more than one boat. That would be a problem for business if you had down time and had a lot of clients booked.
More hp does not have to come at the expense of higher compression of more fuel. You just have to use what you have most effectly. Alot of tines there is more fuel due to bad adjustments, thst us not being burnt or wasted. Doing things to make the motor more efficient makes my hp without adding more compression or heat. In fact burning all the fuel the correct way will actually decrease temps. Things like correct cans having enough lift and duration matched to head flow. Heads thst flow better or actually have more velocity will mix the air fuel better making more hp. You can add 20 to 50 hp to most 260hp 5.7s and not have to touch pistons. Alot of time 205hp can be gained in just carb and intake. Another 20 to 30 easy with heads and valve work done correctly. Nothing about cam and pistons changed. And carbs can be set up to be quite effenent. But they take work and adjustments where fi just does all that for you