200 EFI Problems

[prc4816]

I have a 200 EFI ser# OT148526. On an outing about a month ago, it took off from the ramp like normal, and ran fine. Later that afternoon it started not wanting to come up on plane, and would only top out at low 50's, where it would normally run mid 60's. On that day it seemed to be running rich. After bringing the boat home, 2 of the plugs looked fouled, so we replaced all plugs with recommended (NGK's I think). Running on a hose, all cylinders tested good for spark. I took the boat back out, and it still didn't want to come up, and ran slow again. I brought the boat back, made sure all battery connections were good, and tried to look at and insure all harness connections were solid, but the boat is still running the same. My tachometer was reading high in the few outing before all this started. The day all this started, my water pressure gauge was showing high as well, I did not get any alarms though, and the alarm does chirp when I first turn the key. With the tach acting up, I thought maybe a bad ground, but haven't found anything yet. Motor doesn't sound bad like it is missing or anything, just has not power. I need some ideas as to where to check next, or what might be causing this. I plan on checking compression next, just to hopefully rule anything in that realm out. Any ideas or help would be greatly appreciated.

[Wildcat Dude]

You should ONLY be running these plugs NGK# BPZ8HS-10. Your tach is telling you something is wrong - you'll need to inspect CLOSELY all electrical components and connectors for ANY signs of discoloration/burnt/off color - anything at ALL not normal. Take it to the shop is my recommendation and get the readouts. Make sure the cannon plugs are clean (internally - undo the connectors).

[EuropeanAM]

You will definitely need to get it checked out- PREFERABLY before running it again. Start with the BASICS:

-Compression Test
-Spark Test
-Fuel Quality, Pressure, and Delivery Tests
-Visual inspection of VOLTAGE REGULATORS/Connectors

[prc4816]

You should ONLY be running these plugs NGK# BPZ8HS-10. Your tach is telling you something is wrong - you'll need to inspect CLOSELY all electrical components and connectors for ANY signs of discoloration/burnt/off color - anything at ALL not normal. Take it to the shop is my recommendation and get the readouts. Make sure the cannon plugs are clean (internally - undo the connectors).

Just out of curiosity, what all does a readout show?

[EuropeanAM]

Just out of curiosity, what all does a readout show?

On this particular serial number, you would only see LIVE data (or actively occurring faults). No historical memory (faults or hours) are stored in this (Cummins-style) ECU.

[prc4816]

Thanks, I was just curious. Also is there any test for voltage regulators? I have been keeping my eye on them for a while, but the terminals/wires/regulators look ok. I had a bad cranking battery a while back, and it caused my tach to read funny. I guess it was overworking the regulators. Could these also cause the boat to lose power?

[EuropeanAM]

Thanks, I was just curious. Also is there any test for voltage regulators? I have been keeping my eye on them for a while, but the terminals/wires/regulators look ok. I had a bad cranking battery a while back, and it caused my tach to read funny. I guess it was overworking the regulators. Could these also cause the boat to lose power?

Yes, they can. Tests are outlined in the OEM Mercury Service Manual (they will catch approximately 70% of failed or failing regulators).

Approximately 85% of failed/failing regulators can be diagnosed with a set of eyeballs, monitoring tach function, and monitoring BATTERY VOLTAGE at the battery (for LOW or HIGH voltage).

[prc4816]

VR's seem to make sense to me. I will try and pick up a manual. I've got access to to volt/ohm meter and someone who is pretty good with it. Thanks for the help Don.

[STCL01]

Subscribed to this thread. I'm still having similar issues with a 97' Merc 175 EFI. I'd be interested to see what you find. As for the tach, I can't remember if your motor has two voltage regulators or not. The tach runs off the VR on some motors. If I remember correctly there is a gray wire that runs from the VR to the tach. First look at the plus on the VR and see if they look burnt or the wiring insulation is hard and brittle. If so that signifies heat and a bad VR. You can swap your tach wire to the other VR and see if it works correctly, presuming that you have only one bad VR and also presuming that your engine has two VR's. I'd still be interested in what you find as the cause. I have and issue where my boat would suddenly not get up on plane. I went through the fuel side down to the injectors and cleaned everything. Took it to the lake and it ran but with a throttle issue and maybe a miss. At that point I took it into the shop. I had inadvertently gotten one of the synch levers off 180 degrees which was my throttle issue. They reset the synch and timing. Took it back to the lake and it ran at 1800 rpm under load and would not plane. So it's back to the shop for them to lake test it since they don't have a tank and a load prop. We will see. I will also let you know what is found on this end.

[Wildcat Dude]

Subscribed to this thread. I'm still having similar issues

As you are still having issues please start a new thread with your symptoms and SN so as to not confuse what the original poster is wanting help with and possible answers for others to review. What is being done to your motor doesn't necessarily mean it will work for his issues.

[STCL01]

As you are still having issues please start a new thread with your symptoms and SN so as to not confuse what the original poster is wanting help with and possible answers for others to review. What is being done to your motor doesn't necessarily mean it will work for his issues.

To the OP, I did not intend or attempt to hijack your thread. Just seemed that we were having similar problems with a similar powerhead and might be able to share information to our benefit. If the OP took it the way that Wildcat Dude appears to have then I apologize. If Wildcat Dude would like to continue this conversation he is certainly able to message me, and we can continue this off-forum. Hate to get off point you know.

[EuropeanAM]

Though your engine's share similarities in the powerhead, intake and ECU, there are MAJOR differences in the electronics.

Always best to keep separate engines (and problems) in separate posts.

[STCL01]

Point taken, Don, and thank you again for your prior help to me on this issue which I did post in a separate thread. Eventually we will narrow it down and find the cause.

[Wildcat Dude]

Sorry man - never could write love poems

[STCL01]

Sorry man - never could write love poems

No apologies needed. Should probably be the other way around. You caught me on a bad day. Sorry, Wildcat Dude!

[Wildcat Dude]

Hey, no problem man, I have LOTS of days like that. Its awful hard to express oneself on a keyboard. Granted I was a certified ahole for 24 years (cop) , I tend to just cut to the chase - other times say more than I should (that ALWAYS got me in trouble) especially with politicians that would tell me how to do MY job. Now I deal with them at the VA disguised as doctors. So I understand and don't let it bother me. Its a wonder I got my 2nd wife going on 35 yrs with me Hope you get that motor issue worked out though, I'd like to see the end result of fix for it. Don and Sherm (among others) have taught me a LOT. Good luck.

[STCL01]

I guess I am a certified a-hole too, at least according to my wife. I am an attorney, and I represent the cops and municipalities when they get sued. I am used to being blunt. So sometimes it just comes out wrong. I will let you know on the boat. It is killing me to not be able to use it. Now I guess we had better let the OP have his thread back! Have a good one!!

[Wildcat Dude]

Hope he gets back and gives us update soon - the suspense is killing me.

[EuropeanAM]

No problem.

Might want to post updated info on your previous post (it's now well-buried).

[STCL01]

No problem.

Might want to post updated info on your previous post (it's now well-buried).

Thanks, Don. I will when I have something to post. They are to lake test it today or tomorrow. Hopefully they can figure out what is wrong with it. If and when, I'll update the old post to bring it to the top. I sure need the boat back. We have a trip to Caddo Lake coming up!