Please help! 2007 optimax 150 problems

vroom ZOOM

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Aug 15, 2017
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just checked my opti, it will hold 10 psi in the fuel rail for a while after turning the key to on without starting it. Check this!

This can mean two things:
An injector is leaking (need to service injectors anyway)
bad regulator/tracker

could be a worn fuel pump but then at WOT you would have problems.
 

Dhott

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Oct 5, 2021
Messages
18
just checked my opti, it will hold 10 psi in the fuel rail for a while after turning the key to on without starting it. Check this!

This can mean two things:
An injector is leaking (need to service injectors anyway)
bad regulator/tracker

could be a worn fuel pump but then at WOT you would have problems.
I’ll get a better video of that here in a little bit. What would you consider a while? And would it be a leaking air or fuel injector?
 

Dhott

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Actually no reason for a video. Just tested the pressure again and it held right at 10 for several minutes. The needle never moved at all and I eventually just unhooked it
 

Dhott

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Oct 5, 2021
Messages
18
just checked my opti, it will hold 10 psi in the fuel rail for a while after turning the key to on without starting it. Check this!

This can mean two things:
An injector is leaking (need to service injectors anyway)
bad regulator/tracker

could be a worn fuel pump but then at WOT you would have problems.
The only place I can run the motor is on the water and I’m going to be on the water a lot this weekend so if you can think of anything I should test please let me know. I got the reading of the pressure in my garage and it held steady at 10psi. Maybe after I run it the diaphragm heats up and leaks? I dont know. Im just guessing. I’ll get more pressure readings and test spark once again this weekend. Maybe since I found one bad coil I stopped thinking about it. I wouldn’t think there’d be two bad coils and it still run ok but I’m going to test that. Correct me if I’m wrong but if there was a bad injector it would through a code right? But if there was just a clogged injector it wouldn’t throw a code? Thank you so much for all your help
 

vroom ZOOM

Petty Officer 1st Class
Joined
Aug 15, 2017
Messages
254
Actually no reason for a video. Just tested the pressure again and it held right at 10 for several minutes. The needle never moved at all and I eventually just unhooked it
can you take a video of the fuel mist coming out of the air rail? Also unhook the TPS linkage and let the TPS fully seat down the the idle position on its own. You might try even pushing it down a little. See if this makes it run better. Also do a cylinder drop test by unplugging an injector 1 at a time, and see if it slows down any. Lets try do as much testing as possible before starting to dump money into it.
 

vroom ZOOM

Petty Officer 1st Class
Joined
Aug 15, 2017
Messages
254
The only place I can run the motor is on the water and I’m going to be on the water a lot this weekend so if you can think of anything I should test please let me know. I got the reading of the pressure in my garage and it held steady at 10psi. Maybe after I run it the diaphragm heats up and leaks? I dont know. Im just guessing. I’ll get more pressure readings and test spark once again this weekend. Maybe since I found one bad coil I stopped thinking about it. I wouldn’t think there’d be two bad coils and it still run ok but I’m going to test that. Correct me if I’m wrong but if there was a bad injector it would through a code right? But if there was just a clogged injector it wouldn’t throw a code? Thank you so much for all your help
plugged injector doesn't throw a code. There was a recall on the coils, see if your merc dealer can get you some free ones if you find another bad one. The service bulletin calls for all coils to be replaced.
 

Dhott

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plugged injector doesn't throw a code. There was a recall on the coils, see if your merc dealer can get you some free ones if you find another bad one. The service bulletin calls for all coils to be replaced.
So I did a drop test on injectors and coils. Cylinder 1 didn’t change much when I disconnected the injector. Swapped 1 and 2 injectors and it still didn’t change much when I disconnected cylinder 1 injector. I then disconnected coils and cylinder 1 coil didn’t really change how it was running at all. I’d say my problem is in cylinder number 1. Is there a way to test an individual coil? And would it make sense that at idle the coil doesn’t produce a strong enough spark but once I give it throttle the coil works?
 

vroom ZOOM

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So I did a drop test on injectors and coils. Cylinder 1 didn’t change much when I disconnected the injector. Swapped 1 and 2 injectors and it still didn’t change much when I disconnected cylinder 1 injector. I then disconnected coils and cylinder 1 coil didn’t really change how it was running at all. I’d say my problem is in cylinder number 1. Is there a way to test an individual coil? And would it make sense that at idle the coil doesn’t produce a strong enough spark but once I give it throttle the coil works?
did you change both the air and fuel injectors?
 

Dhott

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did you change both the air and fuel injectors?
I just ran the boat with a new coil on cylinder 1. Ran MUCH better. Still a little rough at idle though but gained some top end rpm and felt like it just had a lot more get up and go. I think the cylinder 1coil was totally shot and there might be another coil on its way out. Do you know how to ohm test the coils? Also do you know the serial number range for the coil recall?
 

Dhott

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Also since it’s not the original powerhead the serial number on the transom bracket isn’t the correct one. I’m having trouble finding a serial number on the actual powerhead
 

vroom ZOOM

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254
I just ran the boat with a new coil on cylinder 1. Ran MUCH better. Still a little rough at idle though but gained some top end rpm and felt like it just had a lot more get up and go. I think the cylinder 1coil was totally shot and there might be another coil on its way out. Do you know how to ohm test the coils? Also do you know the serial number range for the coil recall?
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vroom ZOOM

Petty Officer 1st Class
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Aug 15, 2017
Messages
254
Also since it’s not the original powerhead the serial number on the transom bracket isn’t the correct one. I’m having trouble finding a serial number on the actual powerhead
STBD cylinder head near PCM, or under alternator, or there is someplace else where its stamped in a plug on the powerhead. And, i would recommend to get those injectors cleaned... or you may soon need another powerhead. It's not expensive, and gives peace of mind, and more power if they were really plugged up.
 

Dhott

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Oct 5, 2021
Messages
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STBD cylinder head near PCM, or under alternator, or there is someplace else where its stamped in a plug on the powerhead. And, i would recommend to get those injectors cleaned... or you may soon need another powerhead. It's not expensive, and gives peace of mind, and more power if they were really plugged up.
Hey i know it’s been a while. I think I’m making some progress. I’ve now replaced three coils. It runs a lot better all around. Still have a slight cough at idle and doing a drop test the cough is still there with any of the cylinders unplugged so I think it’s something that’s affecting the whole motor. Possibly a diaphragm? One thing I’ve noticed is before the powerhead replacement my voltage gauge showed like 14 volts while on plane and around 13 volts around idle( or something like that). Since the new powerhead it’s showing around 11.5-12 around idle and just slightly more than that on plane. When idling I put a meter on the battery and that meter is showing higher voltage than what the gauge it’s showing. I can’t remember exactly but I think around 14 volts. I just think that’s kind of odd. Could it be possible that even though the alternator is clearly working, the motor is not getting all those volts? Or what else should I look at?
 

vroom ZOOM

Petty Officer 1st Class
Joined
Aug 15, 2017
Messages
254
Hey i know it’s been a while. I think I’m making some progress. I’ve now replaced three coils. It runs a lot better all around. Still have a slight cough at idle and doing a drop test the cough is still there with any of the cylinders unplugged so I think it’s something that’s affecting the whole motor. Possibly a diaphragm? One thing I’ve noticed is before the powerhead replacement my voltage gauge showed like 14 volts while on plane and around 13 volts around idle( or something like that). Since the new powerhead it’s showing around 11.5-12 around idle and just slightly more than that on plane. When idling I put a meter on the battery and that meter is showing higher voltage than what the gauge it’s showing. I can’t remember exactly but I think around 14 volts. I just think that’s kind of odd. Could it be possible that even though the alternator is clearly working, the motor is not getting all those volts? Or what else should I look at?
Easy to check. Check the voltage directly on the motor. I suggest that you check your handheld meter by unhooking the voltage gauge and measuring directly at the voltage gauge. Also, what caused the old powerhead to blow? Did you get a fully dressed powerhead, or did you use all the parts from the old one?
 
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