Twins DF175A both running rough

[blbaker88]

A new update from my mechanic...

Suzuki sent out a Southeast Regional Tech Rep. He agrees with my mechanic that according to the diagnostic testing the engines should run fine. They are convinced it is a timing issue. I agree on timing being the likely issue, but they think it is mechanical not electrical and to that end are now replacing the cam shafts. I specifically asked about the crankshaft and cam shaft position sensors, he said they tested the sensors, and they were found to be good. To my relief the local mechanic did agree that all this troubleshooting time is on their dime.

[redlowrey]

You are going to kick your self if you find out that you had put oil that had a too higher viscosity in the engines and the inlet phaser was advancing the camshafts way to early because of the higher oil pressure. Think about it all you done was change the oil, when you started the engines the phasers would have been in the fully retarded position idling, and when you opened the throttle the oil pressure increases then unlocks the phaser and advances the camshaft.

If the oil was too thick the phaser is going advance or retard at a different time to the rpm and throttle position because of the higher oil pressure at a given throttle opening.

[blbaker88]

The oil used is Suzuki's oil (ECSTAR V7000 10W40) and is what is recommended by Suzuki. So unless their distributer put the wrong product in the jug, I don't see this being the issue.

[redlowrey]

I met with the mechanic today. He believes he has found the issue. He found the port engine had jumped time. Reset the timing and he said engine now runs fine. He plans to do same to starboard next week. So asked what can cause both engines to jump time. He reluctantly told me ha had a suspicion. He suspected running the boat aground could cause this to happen. Perhaps he is correct. However, in this case that absolutely did not happen. So now I am not sure I can ever trust these engines again. What else can make twin engines at 200 hours jump time within in a few seconds of one another? Then as another blow, the adjustment and troubleshooting hours may not be covered under the Suzuki Extended Protection Plan.

This just dont add up your mechanic said one engine jumped time and he fixed it then he done the same to the other engine and it moved the miss from 2 to 4, do you realize you have to remove the engines from the engine holder to get access to the timing chains and tensioner.
Now you say the camshafts are faulty, on both engines and all you done was change the oil. I could understand that the pressed on timing reluctor on the end of the cam could move and upset the timing but on both engines at the same time, i cant swallow that, plus a timing code would have come up.

Mate there is more to the story than what you are saying.

[blbaker88]

Correction, It is unclear to me if he adjusted the timing on both engines. The mechanic had originally stated that the engines jumped time. He based this on his description that it appeared that the chain link and gear mark, or the gear marks did not align, "appeared to be off by one tooth". He adjusted the timing, realigning the gears and the chain. Originally, he said this corrected the issue. However, He only fired the engine up briefly. After running the engine for more than just a few seconds he discovered the timing adjustment caused the misfire to move from #2 to #4. He has since readjusted the timing and is now replacing the cam shafts. I confirmed they are only working on engine until they solve the problem. I do not doubt there is more to the story, I only know for certain my role, and that is as I previously stated, that a few weeks prior to the failure, I changed the oil. I do not believe changing the oil had anything to do with the failure. I have almost always performed my own service. I am diligent to follow the prescribed maintenance schedule. I use the parts and fluids recommended by the manufacturer. In this case it is Suzuki's recommendations and requirements that I have followed.

[blbaker88]

Also, yes I am aware of the extent to which the engine is being disassembled to make these adjutemts/replacements. It is bothersome to me that I now have reassembled engine(s). And while by the calendar these engines are 5 years old, to me they are new.

[Solarman]

I think I could understand running through a large clump of seaweed floating below the surface, causing both flywheel keys to shear-off and changing the timing, but both camshafts... let's be real? These motors are not old.

Let's just say sunspots/solar flairs affected two timing sensors and now they're a couple degrees off. That seems more likely?

Good luck blbaker88, I feel your pain.

[redlowrey]

Good call solarman, but if that was the case the check engine light would have come on with a crank cam correlation error. He was adamant that it never hit anything and I think the props would have spun on the hubs before any damage occurred.
When you listen to it idle it sounds more than just a single cyl misfire.

It is strange that there were no codes present and the way they were running you would think a map sensor code would have been present because the manifold vaccuum being effected. I feel for the bloke you just change the oil and end up in a world of hurt.

The crank sensor for these engines are on the outside of the flywheel, not on the inside like a two stroke with the trigger coils on the inside of the flywheel. it works in conjunction with the two cam sensors

[Moonlighter]

Any chance there was a storm in the area between when the engine was last used and the day where it started to run badly? Maybe a lightning strike nearby?

[blbaker88]

At this point if someone said you ran your engines while Mercury was in retrograde and that caused them to fail, I'd say ok, but how do I fix it? I live in Florida, for you guys not on this side of the pond, that is the southeastern United States. We get our fair share of thunderstorms. I do not specifically recall a bad electrical storm, but it is possible. When not in use the boat is on a lift with a onboard battery charger plugged in. The battery switches are kept off when not in use. If it were damage to a component due to lighting or other electrical surge, it seems it would have instantly malfunctioned. As the case is it ran at idle and slow speed for several minutes.

[artdf175]

Did the dealer try a new or borrowed ECM just to rule that out?
This string has got so long but are your engines under warranty?
If so, it is going to be far cheaper for the dealer to just replace them.

[blbaker88]

The ECM was replaced during the first week in the shop., That was several weeks ago. The engines are under the SEP, no longer under the Suzuki warranty.

I have not heard anything since the mechanic swapped out the cams. Since he has not called, I am guessing it did not fix it.

[Solarman]

Ok, I think we need to get back to commonalities. Something that's common to both motors. I just can't believe two motors can fail doing the same thing within moments and believe/ think mechanical problems are the cause.

I think we need to focus on the two things common to both motors. Voltage and fuel seem the only common points. If fuel has been eliminated then voltage could be the issue. Corrosion can cause problems with voltage and be overlooked / not noticeable. The common point for voltage would be the isolation switch and the wires connecting through the switch. If there is corrosion inside (not-visable) the connecting wires to or from the isolation switch (or the switch itself) it could affect the voltage needed for both motors to run properly, as both motors need proper voltage to run smoothly. Would a voltage drop due to corrosion inside the wires/battery cables cause enough impedance to affect how the motors run? And yes, corrosion can cause strange things, and not be visible.

Just trying to find answers here, we don't like not knowing the answer, and I'm sure blbaker would like to know.

Ask Moonlighter if corrosion can be unseen?

[blbaker88]

Solarman, I definitely want to know...I was told that Suzuki's regional tech spent several hours with the local mechanic troubleshooting. They are convinced its a timing issue.

I would think that prior to swapping out $1000.00 worth of cams that they would have eliminated corrosion, spark plugs, and such. For what its worth I am pretty persistent when it comes to keeping wiring terminals, lugs, and battery connections clean and corrosion free. Since I have owned this boat, I have never seen anything more than light tarnish on the copper lugs at the battery terminal.

[Solarman]

It's not the visible surfaces...it's the copper wiring inside the cables insulation that may be corroded? Not visible from the outside.