Merc's External 2 Stroke Oil Tank.-

[Sea Rider]

This 2 stroke Merc EFI 150 HP was running strong and then suddenly the alarm indicating Low Oil chimed in limiting the revs to 2 K. New oil was added to max level, close oil cap, started the motor till warmed up, but now doesn't run as strong as before.

The Service Manual indicates that after adding new oil into the reservoir, must place the cap tight, then open it a bit, start the motor and check that oil is being deliverd to the motor and then procede to screw the cap tight. Question : Does the cap has an air valve of some kind, if some air has managed to pass to the motor from the near empty reservoir, the motor may lose its agility ?

Happy Boating​

 

[Dukedog]

what year?.. regular 2 stroke or opti?

 

[Faztbullet]

Has to be a Opti if it went into Guardian mode as if regular EFI has no limiter. If regular EFI and it dont run as strong as it did you need to check compression.

 

[racerone]

Some oil tanks get crankcase compression on them to help oil flow to the motor.----Tank on motor is kept near full.-----System has a bleed off feature so oil tank is not under pressure during storage.

 

[Sea Rider]

It's the same motor we discussed about many moons back : Don't know which year it is ? So this motor has an internal oil tank besides the external one ?​

The motor was recently serviced, has 50 clock run hours. Sorry but compression can't go wrong between low oil alert and full oil refilling. So what's mentioned in the Service Manual about the oil refill procedure applies or not as probably there's air bubbles somewhere between the external and internal oil tanks ?

Happy Boating​

 

[racerone]

Post some pictures with cowling off this thing.

 

[Dukedog]

thats why i was askin'............. oiler anything has nothin' ta do with tha runnin' part of it.. no guardian (limp) mode.. ya got something else goin' on.............

 

[Faztbullet]

Sorry but compression can't go wrong between low oil alert and full oil refilling.

Oh your so wrong...... You may be a little out of your league as need some special tools to test and reset (DDT). If in Guardian it will only allow RPM up tp 2000rpm. Might be best to tell owner to have a Mercury dealer service it. This motor has the triple nickel brain..

 

[Dukedog]

Faz... plain 'ole (switch box maybe) efi motor.. no nothing' but a buzzer.

 

[Sea Rider]

Oh your so wrong...... You may be a little out of your league as need some special tools to test and reset (DDT). If in Guardian it will only allow RPM up tp 2000rpm. Might be best to tell owner to have a Mercury dealer service it. This motor has the triple nickel brain..

As most of the time drawing wrong conclusions, this is an oldie 2 stroke 150 HP EFI motor with a buzzer and digital low oil level alarm inside the multi function tach, probably comparing to a next level more sophisticated 150 HP motor ?

The motor is working fine after the low oil warning cleared itself off after a full oil refill, according to the owner seems to be revving slight less at wot than he thinks was revving at before the low oil signal chimed in.

Tested yesterday with 2 up and the motor only achieved 4K while running at 50Km/H which is extremely poor. There seems to be an issue with the remote box which isn't letting the motor to accelerate further up. Nope the boat isn't waterlodged, it's taken out of the water after returning to terra firme and stored at a sunshined open patio.

Happy Boating​

 

[Sea Rider]

Removed the cowling to take some pictures, after a close manual inspection 2 plugs's caps were just making slight contact on top plugs, the moron forgot to insert fully in both caps. All 6 doesn't look like were brand new as the pseudo mechanic swore they were. How can you call back a mechanic who's cheating on you...



Next to come is to remove all six spark plugs clean them out, gap them right to 1.0 mm or install new ones depending on condition found, unscrew the external tank cap a bit, start the motor, once warmed up screw the cap back tight as to follow what's recommended in the Service Manual. For that will need to wait for the owner to come back from a trip.

Happy Boating​

 

[Faztbullet]

Yep its a 2.5 not they 3L. Cowlings look the same from the angle it was shot. If its down a 1000RPM it has lost a cylinder.

 

[QBhoy]

It's the same motor we discussed about many moons back : Don't know which year it is ? So this motor has an internal oil tank besides the external one ?​

View attachment 337614

The motor was recently serviced, has 50 clock run hours. Sorry but compression can't go wrong between low oil alert and full oil refilling. So what's mentioned in the Service Manual about the oil refill procedure applies or not as probably there's air bubbles somewhere between the external and internal oil tanks ?

Happy Boating​

Searider. Honestly now...I can assure you that the engine can and will..throw its internals, out the side of the block, between the alarm and you filling it up. Never mind lose compression. These things are famous for it. Sometimes you don’t even get an alarm at all. Hope all is well and not as disastrous as I’m assuming.

 

[Sea Rider]

Thanks QBhoy for your concern, to start with it's not my watercraft, helping my club's boating mate to have a better water experience as he's not been having one since he bough the combo. Before the low oil alarm of the external tank chimed in the motor was revving 4 K and achieving barely 50 Km/H, discovered 2 spark plugs caps not making a good contact. Removed all 6 plugs, cleaned and re gaped them right including shinning the internal metal contact of each spark plug's cable.

Now accelerating evenly idle to max hammer down but only achieving 4200 wot revs with just 2 up, not sumo boaters though. Top speed on flat calm water cond has been increased to 58 Km/H which it's still lousy. Let me tell you that that 150 HP motor is an Olympic Fuel Sucker, will bankrupt anyone. The motor has clocked around 1200 worked hours from brand new.

A cylinder compression test will be mandatory, but don't want to be very picky with owner as he's at the boating learning curve and trusts his current mechanic. The current prop it's a Mercury Mirage Plus 19 pitch prop, how much pitch will the motor need to drop to achieve it's max wot rpm range which is 5600 ? The boat is used with 2 min, max 4 up, all medium light passengers. Right now revving 1,400 less wot revs than max. If pulling all 3 black plugs out, will the wot revs be increased ?



How much wot revs will be increased if going for same prop model with 15 pitch, probably insane going that way by any Prop Calculator parameters, thoughts ?

Happy Boating​

 

[Faztbullet]

Those are Mercurys PVS plugs and are for acceleration purposes only.. If his mechanic is Mercury trained ,they need to test compression and TPS setting.

 

[Sea Rider]

The Merc techie has got C19 so out of business for a long time, can take care of the compression tests myself, for the TPS will need a special tool, where is the TPS located, is it left or right of motor as seen from behind ?

If the TPS setting is correct and the motor is bit low on compression, is it possible to increase the wot rpm towards its max 5600 rpm range going for same prop type with say a 15 pitch ? What compression numbers to look for, some say mim 100 , max 130 PSI, is that correct ?

Happy Boating​

 

[Faztbullet]

TPS is on right side and dont touch it unless you know how to test/set it. There is no cure for low compression. Here is compression recommendation from manual.

 

[Sea Rider]

TPS is on right side and dont touch it unless you know how to test/set it. There is no cure for low compression. Here is compression recommendation from manual.
View attachment 338226

Thanks, will take advantage to test each individual ignition coil with a spark tester to check if all 6 are doing their homework right independently of the cylinders compression test. Will post whatever is found in a few days...

Happy Boating​

 

[Faztbullet]

Those are CDM modules

 

[Sea Rider]

Those are CDM modules

Being individual modules can't be tested individually with a spark tester, say the one with a special light bulb in middle of both cables ? If so, which kind of tester will need to count with for such task ?

Happy Boating​