92 Mariner 150 Idles, but no power on High

[1992ProCraft]

I was crusing at full throttle when all of the sudden I loss power and it came to a halt. It will start and idle. I can give it a little gas and it took me back to the ramp...vibrated, but it got me back. Brand new fuel pump last year. I haven't had a chance to look into it, but I'm assuming a fuel pressure problem. Any ideas? Only thing I adjusted a few weeks back was the idle screw...cranked it up about 1/8 to bring up the RPMs up a bit.

 

[Jeff_G]

Re: 92 Mariner 150 Idles, but no power on High

Do a compression test.
Check for spark on all 6.
Check that all carbs are full of fuel.
Then you can start troubleshooting.
I would be leaning towards ignition if it happened all of a sudden. Possibly the high speed side of the stator or a switchbox.

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

Do a compression test.
Check for spark on all 6.
Check that all carbs are full of fuel.
Then you can start troubleshooting.
I would be leaning towards ignition if it happened all of a sudden. Possibly the high speed side of the stator or a switchbox.

Thanks for the reply...I just got it. The boat has been inop ever since the problem started back in September. I took a look and both regulators were burnt. I went ahead and followed the steps to check the stator and switches and they checked out okay. I replaced both regulators but that didn't fix the problem. I'm suspecting the stator since the battery is not charging and they do look a little discolored from underneath. I'm about to order a new stator, just not sure if something else could be causing the problem or cause the regulators to burn out...what about the trigger, or coils...

 

[j_martin]

Re: 92 Mariner 150 Idles, but no power on High

Like Jeff Said:

Compression test. If it stuck a piston or 2, spending money on tune up parts won't fix it.

Spark on all 6. Same story

Fuel delivery verified, both good fuel and enough. Same story

Now with that verified, the next step would be to check the stator and the trigger with a DVA.

If I had to guess, and it's only a guess, the regulators shorted, first one, then the other, and warmed up the stator enough to cause a single turn short in a charge coil. Testing with an Ohm meter will not find the fault. A DVA will fer sure.

Post what you find, and someone will direct you to the next step.

Systematic diagnostics is the surest way to limit the cost of parts.

hope it helps
John

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

Like Jeff Said:

Compression test. If it stuck a piston or 2, spending money on tune up parts won't fix it.

Spark on all 6. Same story

Fuel delivery verified, both good fuel and enough. Same story

Now with that verified, the next step would be to check the stator and the trigger with a DVA.

If I had to guess, and it's only a guess, the regulators shorted, first one, then the other, and warmed up the stator enough to cause a single turn short in a charge coil. Testing with an Ohm meter will not find the fault. A DVA will fer sure.

Post what you find, and someone will direct you to the next step.

Systematic diagnostics is the surest way to limit the cost of parts.

hope it helps
John

Not sure about a stuck piston or compression problem (very low hours and just had new reeds about 1.5 years ago) and I checked spark on all plugs. I fired it up after replacing the regs and it runs...just sounds like it's missing and vibrates. Like you said, one regulator totally cooked and the bottom one also but not as much as the top one. Battery is not getting charged (reads about 11V) so it must be running on very low current to the coils. I don't have a DVA or the $ to take it somewhere. I think I'm going to try and get a stator and go from there.

 

[j_martin]

Re: 92 Mariner 150 Idles, but no power on High

Not sure about a stuck piston or compression problem (very low hours and just had new reeds about 1.5 years ago) and I checked spark on all plugs. I fired it up after replacing the regs and it runs...just sounds like it's missing and vibrates. Like you said, one regulator totally cooked and the bottom one also but not as much as the top one. Battery is not getting charged (reads about 11V) so it must be running on very low current to the coils. I don't have a DVA or the $ to take it somewhere. I think I'm going to try and get a stator and go from there.

READ MY LIPS
The sudden loss of power you experienced could have been pistons seizing for any number of reasons, like loss of oil, loss of cooling, fuel starvation or timing fault. Until you verify that the engine is mechanically sound (compression test) all other diagnostics are USELESS.

There is a logical progression to getting to the problem. The way presented is the least expensive and fastest way to resolution.

A DVA is a lot cheaper than a stator, and it's re-usable or re-sellable. At this time it is the best investment of your money toward the resolution.

hope it helps
John

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

READ MY LIPS
The sudden loss of power you experienced could have been pistons seizing for any number of reasons, like loss of oil, loss of cooling, fuel starvation or timing fault. Until you verify that the engine is mechanically sound (compression test) all other diagnostics are USELESS.

There is a logical progression to getting to the problem. The way presented is the least expensive and fastest way to resolution.

A DVA is a lot cheaper than a stator, and it's re-usable or re-sellable. At this time it is the best investment of your money toward the resolution.

hope it helps
John

I hear ya, and totally agree with you. I'm not used to outboards, but if a piston seized...will the engine still run? Are you talking about the ring or wall wearing out enough for no compression. The other clue to an electric problem is that the regs melted and I could see burnt components on the board. I'll do a compression test to see where I'm at. What numbers should I be looking for? I will also double check spark. Which DVA do you recommend? I only have a regular multimeter.

 

[j_martin]

Re: 92 Mariner 150 Idles, but no power on High

I hear ya, and totally agree with you. I'm not used to outboards, but if a piston seized...will the engine still run? Are you talking about the ring or wall wearing out enough for no compression.

You have about as much fire in that engine at full throttle as the fire needed to heat 15 homes in Minnesota in January. A failure can soften a piston, and cause ring failure in a few seconds. The point is that the usual reason for uneven idle is compression. The other point that I'm getting tired of repeating is that if the engine is not mechanically sound, nothing else matters.

The other clue to an electric problem is that the regs melted and I could see burnt components on the board.

The battery charging circuits and the charge coil circuits for the switchboxes are completely isolated from each other. The electrical failure experienced in the battery charging (alternater) portion of the stator usually cause no problem with the rest of it. It's possible, but rare.

I'll do a compression test to see where I'm at. What numbers should I be looking for? I will also double check spark. Which DVA do you recommend? I only have a regular multimeter.

About 120 lbs at sea level, reasonably even between cylinders is more important than actual compression as long as it is adequate. Normally the highest one you read will be normal, with the rest showing wear.

A DVA meter is a peak reading meter, which converts AC to DC (as any ac meter does) and then stores and reports the peak voltage. You can make a DVA adapter from a few inexpensive components that will allow a DC multimeter to give you a valid reading.

The AC range on your present meter reports RMS (root mean square) voltage, which directly relates to the steady state power in the circuit. We don't care at all about that value.

The mercury DVA meter is as good as any. BTW, get a Mercury Maintenance manual for that engine if yer serious about working on it.

hope it helps
John

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

You have about as much fire in that engine at full throttle as the fire needed to heat 15 homes in Minnesota in January. A failure can soften a piston, and cause ring failure in a few seconds. The point is that the usual reason for uneven idle is compression. The other point that I'm getting tired of repeating is that if the engine is not mechanically sound, nothing else matters.



The battery charging circuits and the charge coil circuits for the switchboxes are completely isolated from each other. The electrical failure experienced in the battery charging (alternater) portion of the stator usually cause no problem with the rest of it. It's possible, but rare.




About 120 lbs at sea level, reasonably even between cylinders is more important than actual compression as long as it is adequate. Normally the highest one you read will be normal, with the rest showing wear.

A DVA meter is a peak reading meter, which converts AC to DC (as any ac meter does) and then stores and reports the peak voltage. You can make a DVA adapter from a few inexpensive components that will allow a DC multimeter to give you a valid reading.

The AC range on your present meter reports RMS (root mean square) voltage, which directly relates to the steady state power in the circuit. We don't care at all about that value.

The mercury DVA meter is as good as any. BTW, get a Mercury Maintenance manual for that engine if yer serious about working on it.

hope it helps
John

John, I appreciate you taking time to help out...and deal with my inexperience with outboards
I plan on working on it this weekend. First the compression which should be around 120. I'll also check for spark by pulling each plug and grounding to head and looking for spark (saying this cause that's how I check in autos...not sure if it's different in outboards). BTW, the previous owner was nice enough to hand down the Mercury Maintenance manual. Now, I need to search for a DVA to start the fun process of t-shooting. Any ideas of a good site to get one? Crossing my fingers its just the stator...

 

[CharlieB]

Re: 92 Mariner 150 Idles, but no power on High

Checking for ADEQUATE spark is the test, simply having A spark is not adequate to fire the plug under compression at WOT.

The ignition must make enough electricity to make a spark that will give a sharp hot blue arc across at least a 7/16 inch gap, any less and the cyl misfires, causing the motor to run rough and lack power.

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

Well, finally got a DVA on order...found the OEM Mercury DVA for 100 bones shipped.

I let someone borrow my compression tester and never returned it...can't remember who it was. I'm going to have to get another one...what is the thread size?

 

[j_martin]

Re: 92 Mariner 150 Idles, but no power on High

Well, finally got a DVA on order...found the OEM Mercury DVA for 100 bones shipped.

I let someone borrow my compression tester and never returned it...can't remember who it was. I'm going to have to get another one...what is the thread size?

It uses a standard 14mm thread.

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

It uses a standard 14mm thread.

Thanks for the quick reply.

I was looking through the troubleshooting procedures in the manual and it looks like the only test for both stator and trigger is a resistance check. I've already checked it and they were within specs. Just trying to figure out how to determine if either one is bad...it looks like the DVA will be used to test Switches and input to the Coils...

 

[j_martin]

Re: 92 Mariner 150 Idles, but no power on High

Thanks for the quick reply.

I was looking through the troubleshooting procedures in the manual and it looks like the only test for both stator and trigger is a resistance check. I've already checked it and they were within specs. Just trying to figure out how to determine if either one is bad...it looks like the DVA will be used to test Switches and input to the Coils...[/QUOTE

The Mercury manuals fall short in this department. The resistance checks will not find a single turn short, but that very fault will cause the intermittent faults we're looking for.

Here's CDI's superior troubleshooting guide.

http://www.cdielectronics.com/downl...eshooting Guide 2009 - Mercury 6 Cylinder.pdf

hope it helps
John

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

Thanks for the quick reply.

I was looking through the troubleshooting procedures in the manual and it looks like the only test for both stator and trigger is a resistance check. I've already checked it and they were within specs. Just trying to figure out how to determine if either one is bad...it looks like the DVA will be used to test Switches and input to the Coils...[/QUOTE

The Mercury manuals fall short in this department. The resistance checks will not find a single turn short, but that very fault will cause the intermittent faults we're looking for.

Here's CDI's superior troubleshooting guide.

http://www.cdielectronics.com/downl...eshooting Guide 2009 - Mercury 6 Cylinder.pdf

hope it helps
John

That's great...thanks John. BTW, what size flywheel puller would I need (1.5"-16)? I want to pull the flywheel to check for scuffs just in case the upper bearing is wearing out...when I had it cranked last time I heard some noises from up there, but I think it was due to the missfiring...

 

[j_martin]

Re: 92 Mariner 150 Idles, but no power on High

That's great...thanks John. BTW, what size flywheel puller would I need (1.5"-16)? I want to pull the flywheel to check for scuffs just in case the upper bearing is wearing out...when I had it cranked last time I heard some noises from up there, but I think it was due to the missfiring...

Not sure, they're available on eBay. Just be sure it has a fine thread grade 8 push bolt.

 

[Dukedog]

Re: 92 Mariner 150 Idles, but no power on High

Go here ta see what ya need...............

http://motors.shop.ebay.com/i.html?...ories_Gear&_dmd=1&_odkw=mercury&_osacat=26443

This one does both.............

http://cgi.ebay.com/ebaymotors/Merc...at_Parts_Accessories_Gear?hash=item4838b65901

 

[jackd1023]

Re: 92 Mariner 150 Idles, but no power on High

Hello, have been reading post, and honestly getting aggrivated.

Everyone is trying to figure your problem out.

START WITH COMPRESSION TEST submit results.

CHECK SPARK AT THE SAME TIME WITH A SPARK TESTER, submit results.

THIS IS HOW YOU DIAGNOSE

IF YOU JUST WANT TO THROW PARTS AT IT PUT A MAGNET ON THEM

Please let them help you and follow their requests, It is FREE HELP an they are looking for the cheapest and the correct sollution for you.

<WHEN YOU GO TO THE DOCTOR THEY DONT START WITH BRAIN SURGURY THEY DO TESTS FIRST>

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

Hello, have been reading post, and honestly getting aggrivated.

Everyone is trying to figure your problem out.

START WITH COMPRESSION TEST submit results.

CHECK SPARK AT THE SAME TIME WITH A SPARK TESTER, submit results.

THIS IS HOW YOU DIAGNOSE

IF YOU JUST WANT TO THROW PARTS AT IT PUT A MAGNET ON THEM

Please let them help you and follow their requests, It is FREE HELP an they are looking for the cheapest and the correct sollution for you.

<WHEN YOU GO TO THE DOCTOR THEY DONT START WITH BRAIN SURGURY THEY DO TESTS FIRST>

I hear ya! Waiting for my compression and spark tester to arrive. Also got a DVA since I'm pretty sure it will be something to do with the ignition system (burnt Regs, no power to the Batt). Once I get my tools in, I'll post Compression readings and spark results.

 

[1992ProCraft]

Re: 92 Mariner 150 Idles, but no power on High

Go here ta see what ya need...............

http://motors.shop.ebay.com/i.html?...ories_Gear&_dmd=1&_odkw=mercury&_osacat=26443

This one does both.............

http://cgi.ebay.com/ebaymotors/Merc...at_Parts_Accessories_Gear?hash=item4838b65901

Thanks for the links...