Timing is retarded ;-)

[gsbarry]

I checked my timing today (2015 Merc 3.0) following the service manual procedure (jumper on distributor, cutout switch bypassed). I observed the following:
Base initial timing w/ jumper was spot on at 2* atdc; idle timing w/o jumper was also spot on at 15*, however timing at 3000 rpm was only 22* rather than the 26* the manual calls for. I suspect an internal component in the distributor is failing. Thoughts as to what I should look for?

 

[jimmbo]

Doubt that Engine has a Mechanical Timing Advance, but rather an Electronic Advance.
How long have you had this Boat? Do you have any Service History?

 

[Scott06]

I checked my timing today (2015 Merc 3.0) following the service manual procedure (jumper on distributor, cutout switch bypassed). I observed the following:
Base initial timing w/ jumper was spot on at 2* atdc; idle timing w/o jumper was also spot on at 15*, however timing at 3000 rpm was only 22* rather than the 26* the manual calls for. I suspect an internal component in the distributor is failing. Thoughts as to what I should look for?

Verify the tach is correct in case it is reading higher, or did u reving above 3 k and see advance stopping? Usually this relates to the ignition module failing. The module is inside the distributor

is it down on power ?

 

[Mc Tool]

Do these motors have knock sensors ? Is the fuel high enough octane and fresh-ish . My car needs 95 oct and if I feed it 91 it cuts back on something that noticeably limits hp.....I suspect the ignition advance with fuelling to suit
Not that familiar with newer outboards but I am with mass produced controllers and 4 deg off ( the right way ) might not be that bad . Try it at 3250 rpm and see if it doesnt advance a bit more .

 

[jimmbo]

No Knock Sensors, they are designed to burn Reg Gas.
Comparing a Boat Engine to a Car Engine, is an Apples to Oranges Comparison, even when it comes to Engines like the 4.3, the 5 liter, and the 5.7 liter. Completely different Operational Parameters

 

[gsbarry]

The boat is new to me, as far as I know the prior owner neglected the boat and only did oil changes during his 10 years of ownership. Yesterday was the first time I’ve had this boat out on the water it definitely seemed underpowered, but the prior owner also put the wrong prop on there (which I’ll replace), so I can’t say for sure if the timing is causing a major power loss, but since its out of spec I suspect it is at least losing a bit of power. The tach on my timing light and boat gauge read the same, and the timing advance stops rising around 2400 and above (same advance at 3500 for example). Fuel is fresh and regular octane. I just replaced plugs, wires, cap, rotor, fuel filter, cleaned carb, oil change. Overall she runs well, just don’t want to leave power on the table with an already underpowered motor.

Y’all know if the ignition module within the distributor is available separately on its own? Or am I going to have to buy a whole new distributor?

 

[Scott06]

The boat is new to me, as far as I know the prior owner neglected the boat and only did oil changes during his 10 years of ownership. Yesterday was the first time I’ve had this boat out on the water it definitely seemed underpowered, but the prior owner also put the wrong prop on there (which I’ll replace), so I can’t say for sure if the timing is causing a major power loss, but since its out of spec I suspect it is at least losing a bit of power. The tach on my timing light and boat gauge read the same, and the timing advance stops rising around 2400 and above (same advance at 3500 for example). Fuel is fresh and regular octane. I just replaced plugs, wires, cap, rotor, fuel filter, cleaned carb, oil change. Overall she runs well, just don’t want to leave power on the table with an already underpowered motor.

Y’all know if the ignition module within the distributor is available separately on its own? Or am I going to have to buy a whole new distributor?

The ignition module is available separately. I think if you google delco est module you will find the cross over to the GM module. you are correct to do some basic items if maintenance was neglected. I would hold off on that for now…

if you have the wrong prop that will make an underpowered boat terrible. 3.0 s are no speed demon. What they are is durable and economical. Ran one for many years, propped right it can do ok.you want it propped so you can hit 4600-4800 wot rpm. Go down in pitch to get rpm up. So many people foolishly put more pitch on thinking they will go faster but if engine doesn’t have enough power to swing it it will lug the engine.

also look at the impeller in the drive and the gear Lube in the drive.

 

[gsbarry]

The ignition module is available separately. I think if you google delco est module you will find the cross over to the GM module. you are correct to do some basic items if maintenance was neglected. I would hold off on that for now…

if you have the wrong prop that will make an underpowered boat terrible. 3.0 s are no speed demon. What they are is durable and economical. Ran one for many years, propped right it can do ok.you want it propped so you can hit 4600-4800 wot rpm. Go down in pitch to get rpm up. So many people foolishly put more pitch on thinking they will go faster but if engine doesn’t have enough power to swing it it will lug the engine.

also look at the impeller in the drive and the gear Lube in the drive.

Thanks, I started a separate thread for my prop issue. Leaning towards a 19 pitch, 14.25” diameter Merc 3 blade aluminum. I have also done outdrive work that I didn’t mention, which was replacing the impeller, gear oil, a melted oil seal carrier, and melted pickup tube, main gasket and o ring kit. Also pulled/inspected the exhaust mainfold, which looked good, replaced a melted exhaust shutter. I discovered yesterday I seem to have leaking bellows as well, despite them looking good visually, so the outdrive is coming off again. I’m trying to resolve all the issues in parallel, so I’m going to do something about the timing. It looks like this is the right part number for my motor. $300

 

[alldodge]

Your unable to reach factory WOT so the motor is lugging. It's irrelevant right now if you are or are not reaching max rpm. Do not start throwing parts at your perceived problem until there actually is a verified problem

Y’all know if the ignition module within the distributor is available separately on its own?

Yes it can

 

[alldodge]

Reading your other thread I'm thinking about merging it with this one, because the issues are one in the same

Boat currently has a 17P and you want to go to a 19P which will just slow you down more. What you need to do first

Dump contents of fuel filter into a clear container and see if there is only clear clean gas
Compression test

If those 2 are good set advance at 2* BTDC and see if performance increases. If it does increase check advance to see if it's closer to 26*. If it has look at new module

If it did not, look at carb

 

[jimmbo]

Thanks, I started a separate thread for my prop issue. Leaning towards a 19 pitch, 14.25” diameter Merc 3 blade aluminum. I have also done outdrive work that I didn’t mention, which was replacing the impeller, gear oil, a melted oil seal carrier, and melted pickup tube, main gasket and o ring kit. Also pulled/inspected the exhaust mainfold, which looked good, replaced a melted exhaust shutter. I discovered yesterday I seem to have leaking bellows as well, despite them looking good visually, so the outdrive is coming off again. I’m trying to resolve all the issues in parallel, so I’m going to do something about the timing. It looks like this is the right part number for my motor. $300

It sounds like this Engine may have been overheated. If you have done a Compression Test, what were the Results? If you haven't, do one, before going and spending money.

 

[gsbarry]

It sounds like this Engine may have been overheated. If you have done a Compression Test, what were the Results? If you haven't, do one, before going and spending money.

The compression test results seemed good to me. My results were 171, 182, 181, 171 psi from cylinder 1-4. Others have commented my gauge may be inaccurate as the numbers are higher than expected. Nonetheless the results are all relatively consistent, which I believe is the desired outcome of a compression test. I replaced the fuel filter, which didn't look too bad, but i noticed the paint on the inside of the filter housing was peeling, so i cleaned the housing prior to reinstallation. The tank has fresh fuel. The carb has been removed and sprayed with carb cleaner (not a full bath treatment, but looked good and clean), also replaced the small filter in the carb too which was quite clean, save for a few small pieces of debris in it. I was been having issues hard starting, but was able to resolve that with additional cleaning of the TKS passage in the carb which dislodged a small piece of debris - fires up reliably now. The motor itself seems to run very good. I'm actually hitting too high of rpm's getting out of the hole, it was about 5300 today (which I didn't do for long as I realize that's not a good thing to push). Base timing is set at 2* btdc, idle total advance at 15*, BUT total advance at 3000+ rpm is only 22* (4* too low). If i adjust the distributor position slightly so that base timing is right at 0* TDC (2* advanced from spec), then the idle advance moves up 2* to 17*, and the 3000+ rpm advance also moves up 2* to 24* (which is still 2* too low vs spec although within the +-2* range).

 

[jimmbo]

As other mentioned the module in the Distributor controls the Spark Advance. If it is pooched or is the wrong one(you don't know the Servicing/Repair History), the Timing Advance could be off(man I hate Electronics on engines. My I/O has a Distributor with good old fashioned Weights).
That could also contribute to the lazy hole shot you have mentioned in another thread

 

[gsbarry]

As other mentioned the module in the Distributor controls the Spark Advance. If it is pooched or is the wrong one(you don't know the Servicing/Repair History, the Timing Advance could be off(man I hate Electronics on engines. My I/O has a Distributor with good old fashioned Weights).
That could also contribute to the lazy hole shot you have mentioned in another thread

Agreed Jimmbo. I'll replace the ignition module and report back my timing test results after.

 

[gsbarry]

The compression test results seemed good to me. My results were 171, 182, 181, 171 psi from cylinder 1-4. Others have commented my gauge may be inaccurate as the numbers are higher than expected. Nonetheless the results are all relatively consistent, which I believe is the desired outcome of a compression test. I replaced the fuel filter, which didn't look too bad, but i noticed the paint on the inside of the filter housing was peeling, so i cleaned the housing prior to reinstallation. The tank has fresh fuel. The carb has been removed and sprayed with carb cleaner (not a full bath treatment, but looked good and clean), also replaced the small filter in the carb too which was quite clean, save for a few small pieces of debris in it. I was been having issues hard starting, but was able to resolve that with additional cleaning of the TKS passage in the carb which dislodged a small piece of debris - fires up reliably now. The motor itself seems to run very good. I'm actually hitting too high of rpm's getting out of the hole, it was about 5300 today (which I didn't do for long as I realize that's not a good thing to push). Base timing is set at 2* btdc, idle total advance at 15*, BUT total advance at 3000+ rpm is only 22* (4* too low). If i adjust the distributor position slightly so that base timing is right at 0* TDC (2* advanced from spec), then the idle advance moves up 2* to 17*, and the 3000+ rpm advance also moves up 2* to 24* (which is still 2* too low vs spec although within the +-2* range).

I meant to say the base timing was set at 2* AFTER TDC per the manual for this serial number engine, not before. So then adjusting distributor to 0* advanced all readings by 2*. Again, still a bit low.

 

[ROY WILLIAMS]

I meant to say the base timing was set at 2* AFTER TDC per the manual for this serial number engine, not before. So then adjusting distributor to 0* advanced all readings by 2*. Again, still a bit low.

2 DEG ATDC TIMING DISTRIBUTION 600 RPM - 700 RPM ENGINE.
GASOLINE 87 OCTANE.

https://www.jblllc.com/wp-content/uploads/2015/03/GM-3-L-Service-Manual.pdf

 

[Scott06]

The compression test results seemed good to me. My results were 171, 182, 181, 171 psi from cylinder 1-4. Others have commented my gauge may be inaccurate as the numbers are higher than expected. Nonetheless the results are all relatively consistent, which I believe is the desired outcome of a compression test. I replaced the fuel filter, which didn't look too bad, but i noticed the paint on the inside of the filter housing was peeling, so i cleaned the housing prior to reinstallation. The tank has fresh fuel. The carb has been removed and sprayed with carb cleaner (not a full bath treatment, but looked good and clean), also replaced the small filter in the carb too which was quite clean, save for a few small pieces of debris in it. I was been having issues hard starting, but was able to resolve that with additional cleaning of the TKS passage in the carb which dislodged a small piece of debris - fires up reliably now. The motor itself seems to run very good. I'm actually hitting too high of rpm's getting out of the hole, it was about 5300 today (which I didn't do for long as I realize that's not a good thing to push). Base timing is set at 2* btdc, idle total advance at 15*, BUT total advance at 3000+ rpm is only 22* (4* too low). If i adjust the distributor position slightly so that base timing is right at 0* TDC (2* advanced from spec), then the idle advance moves up 2* to 17*, and the 3000+ rpm advance also moves up 2* to 24* (which is still 2* too low vs spec although within the +-2* range).

have you verified the tach at 5300 is accurate? I don't think the est has a rev limiter, so if you are indeed hitting 5300 watch it as that is above the safe limit for the 3.0.

I had a 91 Sea Ray 170 which is a similar size boat and ran 17" and 19" props and was no where near 5300. This 3.0LX had the distributor less ignition with a coil pack and did have a rev limiter at 5000. the 17 could hit it but the 19" could not.

While a 3.0 is never going to be a powerful setup, I would think if you are able to get a true 5300 at WOT and it is sluggish out of the hole you have a carb or ignition issue.

As mentioned I would set the dist so you get the full 26 degrees advance and see if it helps before getting the parts cannon out...

 

[gsbarry]

2 DEG ATDC TIMING DISTRIBUTION 600 RPM - 700 RPM ENGINE.
GASOLINE 87 OCTANE.

https://www.jblllc.com/wp-content/uploads/2015/03/GM-3-L-Service-Manual.pdf

Thanks for the link to the engine teardown service manual! I searched through that particular manual and didn't see the timing specs listed. What I'm looking at is the below from the Mercruiser service manual 26:

 

[gsbarry]

have you verified the tach at 5300 is accurate? I don't think the est has a rev limiter, so if you are indeed hitting 5300 watch it as that is above the safe limit for the 3.0.

I had a 91 Sea Ray 170 which is a similar size boat and ran 17" and 19" props and was no where near 5300. This 3.0LX had the distributor less ignition with a coil pack and did have a rev limiter at 5000. the 17 could hit it but the 19" could not.

While a 3.0 is never going to be a powerful setup, I would think if you are able to get a true 5300 at WOT and it is sluggish out of the hole you have a carb or ignition issue.

As mentioned I would set the dist so you get the full 26 degrees advance and see if it helps before getting the parts cannon out...

Agreed 5300 is higher than this engine should be ran (manual calls for 4800). This engine has a distributor, and no rev limiter that I observed. From what your describing on your 170, it suggests you could have gone over 5000 rpm with the 17" prop if you didn't have the rev limiter. The tach on the instrument cluster matches the tach on my timing light, so I believe that is accurate. I ran the boat with the initial timing set at 0* tdc, which pushed up idle advance up to 17* and top end advance to 24*. I suppose I could go further and set initial timing to 2* BTDC, which would then put idle advance at 19* and top end advance to 26*. Are there downsides to advancing the initial timing like this? I assume the idle rpm would be raised, which perhaps may cause gear shifting concerns and/or dieseling at shutoff? I wouldn't think 19* idle advance would be severe enough to cause detonation/knock, but maybe it would. I'm not a fan of the parts cannon approach in general, preferring to use pin point diagnostics. But in this case I have some diagnostic info (from the timing light) that points me to the timing module. The special tool needed to test the module itself is about the same price as the module (found new OEM timing module on ebay for $150 from a reputable seller), so I ordered it and we'll see if it improves things.

 

[Scott06]

Agreed 5300 is higher than this engine should be ran (manual calls for 4800). This engine has a distributor, and no rev limiter that I observed. From what your describing on your 170, it suggests you could have gone over 5000 rpm with the 17" prop if you didn't have the rev limiter. The tach on the instrument cluster matches the tach on my timing light, so I believe that is accurate. I ran the boat with the initial timing set at 0* tdc, which pushed up idle advance up to 17* and top end advance to 24*. I suppose I could go further and set initial timing to 2* BTDC, which would then put idle advance at 19* and top end advance to 26*. Are there downsides to advancing the initial timing like this? I assume the idle rpm would be raised, which perhaps may cause gear shifting concerns and/or dieseling at shutoff? I wouldn't think 19* idle advance would be severe enough to cause detonation/knock, but maybe it would. I'm not a fan of the parts cannon approach in general, preferring to use pin point diagnostics. But in this case I have some diagnostic info (from the timing light) that points me to the timing module. The special tool needed to test the module itself is about the same price as the module (found new OEM timing module on ebay for $150 from a reputable seller), so I ordered it and we'll see if it improves things.

No I couldn't go over 5k much with the 17" could only tap it if gas tank was empty and trimmed out.

Only downside to advancing the timing would be detonation potential, if you already bought the module it is a moot point