Mercury 240EFI M2 Full Rebuild Pics

[ddeem]

I have gained soo much knowledge from the website that I thought I would give someting back... After purchasing my boat, the plastic oil pump gear went and #4 seized with #6 on its way out. After getting costs of $4k to $6K for a rebuilt engine, it was upt to me to again fix my issues...

Attached are pictures of the rebuild. I currently have 5 full tanks of fuel thru the motor and the summer has been great...Knock on wood. Engine runs very strong at 6K RPM's. I made the decision to bore the engine to .030 over since two of the cylinders needed this anyway. Probably could have honed the remaining 4 cylinders but ended up with a full rebuild kit off ebay for $900. That plus $129 for new lower end berarings, new oil pump gear $40 and $300 for the bore & hone. So for $1,350 I am fresh and good to go. I will say that it was an interesting rebuild. Many vacume hoses, electrical plugs and fuel system components. I marked with blue tape and a sharpie everything when pulling the engine apart. You can also pull large components as a group ie. coil pack board... Putting back together seemed less confusing that taking it apart. It built well and you just need to take the time and double check the work especially critical parts like rod caps & bearings.

Hope this helps for anyone attempting to rebuild their engines. We really like the Challenger 2000 and now have fresh components which should keep us happy for a long time...

Cheers...Dave

 

[ddeem]

Here are a few additional pics including my wear ring repair. The original seemes to almost have a plastic insert that was 90% gone.. I don't know what was done to it in the past, but it seemed to be non-repairable. After 10 bucks of JB Weld, it was good as new...

The additinal motor shots include the plastic junk part that ruined a perfectly good motor...What a shame that Mercruiser did not use something a little better for the oil injection. The new gear I purchased from the ebay site seems to be a much better plastic..like baked or derlin type of plastic.

 

[ddeem]

Some final pictures.

 

[WAJetboating]

Awesome!

Very cool pictures, thanks for sharing them. I hope to never have some of those views of my engine {grin}, so seeing yours is very helpful.

I agree, a plastic gear on such a critical component was a very poor decision on Mercury's part. I've often wondered why.

Nice job on the rebuild!

 

[WAJetboating]

Here are a few additional pics including my wear ring repair. The original seemes to almost have a plastic insert that was 90% gone.. I don't know what was done to it in the past, but it seemed to be non-repairable. After 10 bucks of JB Weld, it was good as new...

I've never seen a Mercury wear ring look like that. Yuck.

I had a few shallow scrapes in my wear ring, which I too fixed with JBWeld. Then I painted the entire inside surface with Mercury's OEM enamel paint. Looked factory new when done. I also had Impros rework my impeller - it didn't have any damage but there is inevitable wear around the OD so they build that back up, resharpen the edges, and resurface the entire thing.

Nice job all around! Congrats!

 

[ddeem]

For what it is worth, I have a theory on how to save the 240EFI from rod failure... If the motor shuts down, turn the key and try to start it back up right away. If the motor does not turn over it seized up and should be put on the trailer for a motor rebuild. Once it cools a little it will start and run again. I think people let it cool and run again and again until it launches a rod thru the block. Then, it is really game over because you can't rebuild at that point and parts are hard to find. If the motor does turn over after shutting down, it could be another problem including fuel, spark, etc. I will say that I ran mine at idle for a little but not enough to really mess it up as I realized it was no longer smoking. The needle bearings on the bad cylinder were just starting to deteriote and catastrophic rod / block failure was not far away...

Dave

 

[WAJetboating]

I will say that I ran mine at idle for a little but not enough to really mess it up as I realized it was no longer smoking. The needle bearings on the bad cylinder were just starting to deteriote and catastrophic rod / block failure was not far away...

The professionals that modify this V6 2.5L Mercury engine - from whom I've learned a LOT, by the way - all premix their fuel. All of them without exception that I've found. Their feeling is that oil injection failure isn't a question of if, but when.

I haven't gotten to that point yet. Of course, neither do I push my engine like they do, with shaved heads and performance reeds and taller pistons and modified EFI timing (sometimes wholesale replacement of the ECU to get manual control over everthing!) and the like. Those guys really live on the edge.

 

[Dr Honda]

Thanks for the pics! I'm sure that new engine will last a long time.

 

[gskinner]

Due to the same oil gear my engine currently looks just like the pictures. My block is back from the machine shop and hopefully will have it back together within a couple of weeks, if the parts ever show up. It is a shame that the engine relies on that cheap plastic. I guess that is why the newer engines have electric oil pumps.
Fortunately my wear ring and impeller are in great shape and look almost like new.
Can't wait to get it on the water.

 

[WAJetboating]

I've thought about converting my 240EFI to electric oil injection but don't have an answer to the question of regulating the amount of oil based on throttle setting/RPM. The mechanical system does that with an arm off the throttle linkage; there is no variable restriction downstream of the pump itself.

Premix is probably the best choice, since it leaves nothing to fail.

 

[canadianwhiskey]

So did you ever get it back in the water before winter?

 

[ddeem]

If this question is to me, we ran the boat all summer with the rebuild. Over 10 tanks of fuel and motor runs great. We were out every weekend...

Looking forward to the spring!

 

[johnhibbs]

oil gear?

I have a Challenger 2000 with a 240EFI engine and it runs great but after reading this post I want to replace the oil gear. Do you have the part number for the oil gear? I have the manuals but I'm not sure where the gear is. Also, if I premix the gas with oil (40 gallons gas to 1 gallon oil?) do I just leave the oil tank and resivior on the engine empty? Do I need to do anything with the oil lines. Thanks in advance.

 

[johnhibbs]

oil pump drive gear

I just found the oil pump drive gear in the manual. That looks hard to replace. I don't think I would be able to replace that without taking apart the engine unless there is an easy way. Can it be done in a weekend?

I found a place called Marine Solutions Inc that sells after market electronic oil injectors (EOI) for Mercury Marine engines but I don't think they make one for the 240EFI M2 year 2001. I think they cost around $400. Other than remixing, is there someone else that makes a EOI for this engine? Maybe I should just start do the remixing thing. What is the ratio? The oil pump provides 50:1 to 100:1 depending on rpm. Maybe I can put some kind of motor pump monitor on the pump to make sure it is rotating.

 

[saulrwhit]

your my hero!!!!

I want to rebuild mine sooo bad. I purchased my 01 challenger 3 months ago and the story goes, someone didn't take out the plugs while being stored throughout the winter, next spring they figured it out so they ran it at an idle for 40 minutes in the water than started water running it hard and it lost power, local marine shop said 8,995.00 for new motor, installed.... I purchased this nice looking 20 footer for $750.00.........does the rebuild kit come with full specs......this is my first boat and i live in illinois so ive got a few months to go..btw the shop said the block was cracked

 

[johnhibbs]

Eoi

I checked with Marine Solutions Inc. and they do make a Electronic Oil Injector for the 240 EFI M2 engine to replace the crankshaft driven oil pump. It still uses the original oil pump but is driven by a electric motor instead of the gear on the crankshaft. Costs around $550.

They also recommned changing the spark plug from a BPZ8HS-10 to a BUZ8H. Not sure why. Trying to find out.

 

[Racereddie]

From Sparkplugs.com

Surface and semi-surface discharge firing tips are less sensitive to voltage requirement increases due to gap growth(wear). Note the concave cut on the ground electrodes for even Gap growth (wear). In addition, this type of construction aids in burning away the carbon which can act as a bridge between the center electrode and plug shell. This bridging can cause plug misfire.

Eddie

 

[WAJetboating]

I just found the oil pump drive gear in the manual. That looks hard to replace. I don't think I would be able to replace that without taking apart the engine unless there is an easy way. Can it be done in a weekend?

No. It's almost a complete teardown of the engine. The gear is on the crankshaft.

If the reliability of the oil injection is your worry, go premix. Nothing could be safer. Moving to an electric oil injection system just makes you dependent upon a DIFFERENT subsystem, in this case the electrical power bus and the new electrical oil pump motor.

Adding more components and more complexity doesn't usually make things more reliable. Premixing decreases critical parts count. The only downside is potentially greater oil consumption since the ratio isn't varied based on RPM. But there's nothing simpler or more reliable!

 

[ddeem]

I agree with the premixing comment... It is not too bad to do and you could just carry the oil in the boat so it is always around... It is a full teardown to replace the gear. The steel worm gear that rides on the plastic gear eventually gets caught on the seam of the plastic gear and it pops the small allen screw. The new gear is nicer and a harder plastic. I also used JB Weld on the little nubs when installing just in case the new allen bolt would loosen up.

I would think you could just take off the oil pump and pull out the steel worm gear and then replace the oil pump again. Everything would remain but there is no drive then to pump oil. Maybe put a sticker on the gas cap or something as a reminder to add oil...

I read in one thread that Mercruiser had an alarm on the oil pump drive gear that would sound if the drive stopped spinning. It is a shame there is not a kit to retrofit this and I do not know whey they stopped doing this...

Dave

 

[koby6587]

pics rebuilding now

I am currently rebuilding my motor for my 2000 seadoo challenger. My plastic oil drive gear was pretty bad I dont think it would have lasted another season It was about 90 percent worn. I ended up getting aupper rod needle bearings and one of the cylinders bored. 020 over I ordered on oversized piston and 5 sets of standard size rings and honed the others cylinders. By the time I am done I only spent 130 on engine repair 40 bucks on plastic oil gear 200 on complete gasket kit 80 on the piston and I bought 100 dollar manual and torque wrench and other sealents loctites about another120 I spent under 600 dollars. I've dealt with tri state marine off from ebay. I have all of the pistons in the motor currently and just waiting on the gaskets to arrive.


2000 seadoo challenger 240 efi m2 jet pump.

 

[DomsX20]

WOW, its a good thing your doing the rebuild. That worm gear would not have lasted another 2-3 starts..... I am also going through a rebuild on my X-20. Ended up going .030 on 2,4,6 because of the damage caused by the worm gear failure.

Just one question, what prompted you to do the rebuild?? Did you just want to freshen her up? Either way GOOD CALL!!!

 

[koby6587]

WOW, its a good thing your doing the rebuild. That worm gear would not have lasted another 2-3 starts..... I am also going through a rebuild on my X-20. Ended up going .030 on 2,4,6 because of the damage caused by the worm gear failure.

Just one question, what prompted you to do the rebuild?? Did you just want to freshen her up? Either way GOOD CALL!!!

Actually i advanced the timing a little bit and i think it started running hot it shut right downon me and I double checked everything twice it seemed as though the fuel was cut right off. So than it started right back up fine as normal so I.started to take off and it seemed to be fighting its self so I shut it right off. Any ways I pulled plugs and cylinder number 2 had melted metals all over it. I'll put some pictures of what it looked like it was really rough. I'm not sure if the worm gear caused this or if it was my fault with the timing.. anyways it worked out because It soon was gonna be alot worse.

 

[Mario Rosales]

Dear Friends:

I need a little help to know what is the problem with my speedster.
Y boat can´t pass from 2500 rpm and doesn´t move forward. I hear a continue bip until a put in 0 the throtle.

Before that problem, last weekend each 2 minutes a bip was hear and sometimes bip 3 times.
Can anyone tell me what will be the problem??

 

[koby6587]

pictures of the mess

Here is what it looked like when I tore it down

 

[koby6587]

Well popped the motor in bled the oil down to pump double checked everything and finally got to hear what ive been waiting for the last 2 monthes the sound of the motor purring now i just gotta wait till some warmer weather and than break it in!!!!!http://www.seadooforum.com/images/icons/icon6.png