1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

[Mattythemechanic]

I have a mercury optimax 200hp Outboard. Motor has been running great the past 8 times i have taken it out. No problems at all... Cranks right up and gets well over 5000 rpms at WOT... Running it in the gulf all day and was running great then all of a sudden dies like someone pulled the kill switch.... wouldnt restart... had no over heat alarm come on and had plenty of oil and gas. I know optis are very sensitive to voltage and didnt know if some kind of way the battery wasnt being charged and triggered it to go into guardian mode or some other safety precaution. Pulled back to the dock and took to the shop. Mechanic did a full computer test and then a compression test on all the cylinders. had 115-130 psi on all cylinders except the 3rd one... it had about 30 psi... the motor didnt run rough or make any type of loud noise... i was planed out and running for about 20 minutes and just cut off. Has a brand new starter and fuel pump. Mechanic said that i needed a whole new powerhead and would be about 5500 dollars... that seems a little weird to me considering i had no problems and no overheat alarms go off... Motor will crank and run for about 2 seconds then stalls out... Is the mechanic correct on this ? going to ask some friends that work on motors what they think... thanks for your time

 

[Faztbullet]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

Motor will crank and run for about 2 seconds then stalls out...

It seizing up....

 

[Mattythemechanic]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

So what does this mean.... The cylinder with low compression needs to be rebuilt or do i need a whole new powerhead....like i said motor was running amazing no signs of anything thanks fatzbullet

 

[Faztbullet]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

Motor has been running great the past 8 times i have taken it out.

Famous last words just before they pop!!!! Usually when a customer tells me this first thing I grab is compression gauge as 90% usually say it was running great or better than it ever has. I would either upgrade to a newer year engine or install a reman powerhead as the 1999 was a year to itself. The reman will have a 1 yr warranty and the injector needs to be checked on that cylinder.

 

[Mattythemechanic]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

So even if it wasnt running rough or anything it can just go out like that? So i cannot just rebuild that cylinder ? I am not very sure about things when it comes to motors so im just trying to make sure before i spend that kind of money... I guess it just doesnr seem like its possible to be running great with fresh fuel and oil and no alarms or rough running for 30 min at 50 mph and then just stop.... Doesnt make sense.... Again thanks!

 

[jeffersondodson561]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

I would replace that cylinder direct injector and fuel injector as well. These model Optimax's ran really lean, lean makes power that is why it was running great before it failed, and these particular Opti's gave it the name "Opti-Pop". Unless you really trust your mechanic I would seek another Motor. Just my 2 cents.

 

[Mattythemechanic]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

So basically what you guys are saying is there is no other option than to rebuilt the powerhead and cylinders.... So the motor will just run perfect then shut down with no warning? No overheat alarm or anything? Its just hard for me to accept that it just blows like that... Not that by any means i dont believe what yall are saying because i am clueless on these motors... Just wondering if thats the only option and is that definately the problem... Nothing else could cause the motor to stop like a sensor or a fuel related issue?

 

[Faztbullet]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

The only way your going to get a alarm is if a oil or cooling problem occurs. The ECM does not monitor the pistons/moving parts or the injectors per say. You can rebuild it if you want but what type of warranty will you get and you also need to check to see if the engine has had the factory updates as this motor had several. If you let a dealer repair it you can buy a reman cheaper...

 

[Mattythemechanic]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

What updates are required for this motor and does mercury send u the updates free of charge?

 

[jeffersondodson561]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

The reason it is probably not running is because that direct injector is damaged and not allowing the air rail to build up the proper pressure. I know their was an end cap air compressor service bulletin and possibly a direct injector replacement service bulletin. If you go to a Merc dealer they should have access to all the service bulletins via Mercnet.

 

[Mattythemechanic]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

So jefferson u think its a direct injector problem and not an actual powerhead cylinder problem?

 

[jeffersondodson561]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

No if the compression is low you need a new powerhead. I am just saying if one cylinder is low on one cylinder it usually will still run. If that cylinder that has 30 lbs direct injector is damaged it could be affecting the "Orbital Direct Injection" system. If you feel that your mechanic is competent and is giving you the correct information and you are relaying it accurately you need a new powerhead.

 

[Mattythemechanic]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

Right just that one cylinder is low compression so if all the other cylinders are great and just that one is low why would i need a whole new powerhead? Im sorry i just dont quite understand how it works?

 

[jeffersondodson561]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

I am sure you will find some shop to go through the block and make the "necessary" repairs but you will be taking a risk and that "shop" will be the only one to warranty the block. Don't try and rob Peter to pay Paul. Everyone is just trying to help you here, I have seen shops with Dealer signs on the roof that have no clue what they are doing, their are some good ones I am just saying that from my experience you want a reman. Doesn't have to be a an OEM, but a good reman... (I assume these are good?) Get some more free advice.

http://outboardpowerheads.com/

http://www.oneoutboard.com/

 

[Faztbullet]

Re: 1999 Merc Optimax 200 hp. Running great then shuts off with no overheat alarm...

It depends on how bad the cylinder is damaged as you can only bore these so big oversize and it doesnt have a head gasket as it uses a o-ring which I have nor heard of failing. The reason why your limited on boring is you cannot richen the oversize cylinder due to it being electronically controlled. You can easily spend $500 on just repairing the cylinder if it need to be resleeved and this is just the block no parts. If the other cylinders are past their wear limit you are looking at boring the other 5 cylinders and buying new pistons. These run about $150 each so that $750 on pistons,$125 gasket set,impeller,check valves if plugged,injector testing /cleaning and labor. You going to spend about $1500 in labor plus parts so your looking at $3000+ easy and a 60 day warranty from a dealer. The 1998 and 1999 where engines all to themself's and parts will not interchange with the 2000 and up engines as casting differences in block,mounting bosses,different air compressor and fuel rails. You should get a estimate on repair but make sure you setting down as dealer will be way above $4000. Stay away from that oneoutboard place as they used to be Blackbird and have a terrible reputation....