PRO XS 175 ISSUE?

[JOE54]

ah hah

[potomacbassin]

UPDATE - I replaced plugs and belt yesterday. It didn't fix the missing issue. I took the mechanic out on the water today and I was able to replicate the missing. He said that he thinks it's "electrical" but I'm not really sure how he can tell that. I left it there but they won't be able to replicate it in the shop because it occurs anywhere from 4000-5600 rpms. Any other ideas on what to do next and nail down what it specifically rather than throwing parts at it? So far I've:
1. Replaced belt and spark plugs
2. Replaced fuel diaphragm (fixed rough start)
3. Replaced tracker valve (it wasn't the tracker valve)

[leonreno]

Have you had fuel/air pressure check yet? It’s either spark or fuel, have to work to narrow it down. Can a Mercury mechanic run the motor at speed while hooked to diagnostics to determine if any faults or out of spec readings?

[potomacbassin]

UPDATE - Yes fuel/air pressure is within specs. They said they tested all the coils this morning and the number 3 coil is supposed to be 'open' when performing ohms testing but it's reading 18 ohms? They couldn't guarantee that this is the problem but they're going to order a new coil for it. Does this sound right? Could this be causing the problem. I really don't want to just be throwing parts at it.

Second question - He said it was $170 for the part. That seems high to me. Anyone know the part number. Don's site is down.

Third question - Should I tell them I can just install this myself to save on labor? Looks simple. Two bolts and plug?

[leonreno]

Looks like part number is 8M0077471. Online pricing for OEM part is not too far off your quote.

[potomacbassin]

Thanks. So does their diagnosis sound legitimate?

[JOE54]

sounds legit , but heres test,they install coil you and tech lake test or agree you notice improvement , not fix or no improvement no pay, that's how I roll,,my shop fixed or no pay guaranteed , you buy coil its yours mtr still broke

[potomacbassin]

Is installing the coil something that I can do myself?

[ride.race.live]

Yea you can install a coil yourself. very simple. unplugthe wire - undo the 2 bolts holding in place and remove plug cap / wire. and install new one.

[adchunts]

Just replaced a coil on my 175 Pro XS (purchased new in 2011). It is literally a 5 minute job. Plug and play. Used my BBC discount at European Marine (thanks Rhonda!).

[potomacbassin]

Update - So I picked my boat and the new coil up from the shop. I took it home and tried to do ohms test on the bad coil and with the new coil to verify what they were talking about. I forgot to take a picture of the pins so I drew a diagram to show how I numbered the pins. The plug and pins are on the top side of coil when looking at the side. Hope that helps.
They said the ohms tested bad on the #3 coil but when I checked it, I'm getting similar readings on the new coil as on the #1 coil. Can somebody help me out and let me know if I'm missing an ohms test since my service manual is out of date. Or please let me know whether these are within specs. I just touched each pin and moved down the line. I put together a spreadsheet so the results are below. I also noted what setting my multimeter was set at when testing.

See next post.

[potomacbassin]

[EuropeanAM]

It's likely that the coil you are testing has an INTERMITTENT problem, due to poor solder connections on the circuit board. Coil may fail under certain temperature conditions, but pass and function under other temperature conditions.


Have you run the boat to see if your complaint is resolved?

[potomacbassin]

UPDATE - Well just as I thought, the new coil didn't do anything. Missing still exists. I even moved the new coil to each cylinder and nothing helped (I was testing to see if any of the other coils were bad). I have no idea what to test next and neither does my mechanic. He basically told me the best thing to happen would be for me to break down because they can't replicate it at the shop. It misses when getting on plane around 3500-4000ish rpms under load and then at WOT 5620. Any other ideas on what to do next. This is extremely frustrating.

Could this be the computer acting up? Wish someone had a spare computer laying around that I could rent for 15 mins.

[EuropeanAM]

Believe we may have this going via email and post simultaneously... correct?

[potomacbassin]

Yes. Thank you.

[potomacbassin]

Just an update for anyone that follows this in the future. I just ordered a new TPS, lever and cover from Don. I was having symptoms of high reving in neutral after a long run. The only way to get the rpms to settle was to turn the motor off and turn it back on. I'm hoping this symptom is related to the missing in mid rpms and WOT rpms. Hope this works. I believe the next step will be MAP sensor if this doesn't work.

[potomacbassin]

UPDATE - It's fixed. Thanks to Don, he was able to pretty much diagnose it over the phone. He said it's likely due to the TPS. Ordered a TPS, the lever, and the TPS cover from Don which was shipped the same day and had it at my door in two days. He said if it wasn't the TPS it may be the MAP sensor which would've been the next step... however, I've been out two days now without a hickup. So it was the TPS. Thanks again Don for getting me out on the water worry-free.

Summary:
1. Replaced fuel diaphragm because it had a tear in it (fixed rough starts)
2. Checked for spark (had spark in each cyliner)
3. Replaced spark plugs
4. Dealer misdiagnosed my coil as being bad. Replaced #3 coil to no avail. Moved new coil to each cylinder to manually check each coil as well... to no avail.
5. Replaced belt because it was due for replacement (4 years/400 hours)
6. Don diagnosed the TPS over the phone... hooked it up myself and fixed it right up.

[ride.race.live]

been following this thread since the start.. good to hear ya got it fixed!

[SilverFox579]

Great news!