2001 200hp Optimax losing power, with random bursts of power

mustang5

Cadet
Joined
Sep 21, 2010
Messages
27
Hi,

Took the new to me proline 27 walk for its first trip, and after about 4 hours run time, the port motor started losing power.

When it was running, both motors were hitting 5100rpm and it was smooth sailing. Half way through the day, the port motor struggled to start but eventually did.

Later on, the Port motor dropped in revs to about 4300, then would intermittently up in revs back to normal.

Since being at home, I took out the spark plugs to which all looked normally aged, except cyl #3 which looks sparkly clean!!! So I thought it may be compression and having water leak in to that cyl so did a check but all are between 105 - 115 psi.

So with the motor running, if I take off every plug to injector, you can hear the difference, except for when I take it off cyl#3, and this is at idle. I did the same to the starboard motor and also noticed this?? wtf? I have tried change leads from working motor, tried different plug, also changed injectors, tried putting #5 injector plug on #3 but there was no difference.

I put a spare injector on the #3 injector plug and it was working in my hand so there is definately a signal there..

I suppose the question is, will I be able to pin point which cyl is missing at idle??

And why do the 200hp 2001 optimaxs not change in sound when I take the #3 plug off??

I am new to the smartcraft gauges, is there any way of reading a fault from these?

Any help is much appreciated.

Thank you
 

mustang5

Cadet
Joined
Sep 21, 2010
Messages
27
Re: 2001 200hp Optimax losing power, with random bursts of power

Ok,

I also removed the #3 plug on the starboard engine, and it too is the only clean one?? (Like brand new).

Why would both motors not drop rpms in a drop down test, both on #3 which both have the only clean plug?

Seems to get spark, seems to get fuel..and have compression. Am I missing something here?
 

jerryjerry05

Supreme Mariner
Joined
May 7, 2008
Messages
18,183
Re: 2001 200hp Optimax losing power, with random bursts of power

Try swapping coils.See if it follows the coil.What's the model# or serial #s?
Need this to make sure were looking at the right motor.
Profile? Location?You might be close to someone who can help.J
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,935
Re: 2001 200hp Optimax losing power, with random bursts of power

Seems to get spark, seems to get fuel..and have compression. Am I missing something here?
Seems so...:) You really need to test with a gap tester the spark to see if it is hot enough to fire under compression, need to test compression with a gauge and to see if it has enough pressure to support combustion and which injector did you check .the air or fuel one?
 

mustang5

Cadet
Joined
Sep 21, 2010
Messages
27
Re: 2001 200hp Optimax losing power, with random bursts of power

Thanks fellas.

At that stage I had only checked the fuel injectors. I ended up buying an electronic manual and have since narrowed it down to the air injectors on both #3 cylinders on each motor... So basically, I have come to the realisation that the first outing on my new boat I had two motors running 5 cylinders, with the port motor occasionally running at 4 cylinders.....

I then ohm tested them and compared the readings to a working injector and they were the same... I know this does not mean they are not faulty, however gives me some hope of attempting to clean.

What is the best way to shock clean injectors and the merc air/fuel systems, and hopefully free these up?

I have access to quickleen, or is there another product I should use?

Thanks guys.
 

Faztbullet

Supreme Mariner
Joined
Mar 2, 2008
Messages
15,935
Re: 2001 200hp Optimax losing power, with random bursts of power

Label and send all the injectors to Brucatosvs.com and have them cleaned ,flow tested and balanced....
 

mustang5

Cadet
Joined
Sep 21, 2010
Messages
27
Re: 2001 200hp Optimax losing power, with random bursts of power

Took it out today and all ran perfect for about an hour. Put in 150 Gal of top fuel and quickleen, and also drowned motor in power tune before hand :)

So injectors fixed, but believe it or not, I snapped a drive shaft...... Will go on another thread!
 
Top