Low RPM's and loss of speed

[Nutt]

I have a 2013 Mercury 150 4 stroke on a Nitro Z-7. I took the boat out fishing yesterday, and noticed that I couldn't get over 5200 rpm's and couldn't get more than 53 mph. Seemed like I couldn't get any bow lift. I spent a week at Toledo Bend a couple of weeks ago, and she ran great. I normally get right at 60 mph and around 5600 rpm's. While at Toledo, I had to get gas. Could this be the issue? I don't keep a lot of weight in the boat at all, and the fuel is at 1/4 tank, which is where I usually try to keep it.

[Wildcat Dude]

serial #?

[Nutt]

I will try to remember to get the serial number tonight and post again tomorrow.

[EuropeanAM]

In addition to the serial number, a couple other items may be helpful:

-Hours on engine
-Engine last serviced (when)?
-ANY warning horn sounding (or Smartcraft Warning/Alarms)?
-ANY damage to propeller (even the slightest ding or scratch)?

[Nutt]

Ran off and forgot the serial number. The motor was serviced maybe 8 months ago and had 24 hours on it then. I haven't driven it much since, so it probably has maybe 50 hours on it now. There is no warning sound at all, and the prop is still in new condition. No dents, dings or scratches. Im hoping its just a fuel issue. I will take it to the shop, was just hoping someone could give me a "guess" on what they thought. I understand a serial number is needed, so I will try to remember to get it today.

[Nutt]

Finally remembered to get the serial number. It's 1B992937

[EuropeanAM]

Double check your bildge for WATER. If you don't always remove your drain plug, park on a hill and do so (poke something into the opening several times to make CERTAIN there's not water in the bildge).

Could also be the fuel... a running problem due to some failed component, or Engine Guardian (due to some problem that is occurring).

Be sure to report back after it's been checked.

[Nutt]

No water in the bilge compartment. I always take the plug out, and I actually turned on the bilge pump just to be sure. I poked a coat hanger in the drain hole and nothing came out. When I got gas last time, she was pretty low. Maybe a fuel filter is clogged or is getting clogged? I appreciate all of yalls help/direction. Just hoping its something simple.

[Nutt]

Went to the BPS in Bossier City yesterday. They hooked up the motor to their computer and found no problems. Took a fuel sample, and that's the problem. Not a lot of ethanol, but, just bad gas. You could smell how bad it was. Had to come from the last place I fueled up.

[EuropeanAM]

Siphon all of that questionable fuel out- and start with a FRESH load of appropriate fuel.

[Nutt]

Update....got all of old gas out and have run approx. 10 gallons of fresh thru it. Still have same problem. Called another mechanic and he said it sounds like it could possibly be a coil that has gone bad or is going bad? The motor has 39 hours on it, btw. Just cant get the bow up. Another thing I noticed as I was removing the plug and strapping down to the trailer after a tournament on Sunday is the motor seemed to have a "hot" smell to it on the port side. May be my imagination.

[EuropeanAM]

I wouldn't put much thought into that "smell"... as a hot engine (freshly drained of it's coolant) will do that.

A coil is certainly a possibility- though I would think the last shop that checked it over WOULD have checked the BASICS (spark and spark plug condition being one of those items).

[Nutt]

They didn't take any plugs out and look at them. This other mechanic said something along the lines of his computer will test more than BPS's will. Said BPS's computer will only show if the motor threw a code, but his will put a load on everything and tell more? I have not taken the plugs out. I can do that and see if there is any difference between them. I specifically asked about a bad coil when BPS looked at it, and they said that with the low amount of hours, it wouldn't be that or the plugs. The other mechanic said he has seen a bad coil on motors with only 10 hours on it. Also, I asked to see the numbers on the computer or if I could have a print out, and they said I could not.

[EuropeanAM]

ALL Mercury Dealers should have the same Computer Diagnostic System. There may, however, be a difference in the OPERATOR of the computer (knowledge of how to use it, or how to interpret the data and information it provides).

The lack of printouts could simply be a case of no printer configured to the Laptop (or no laptop configured to the engine, also)...

Definitely have to agree- it's NOT a good idea to go with the "New=Good" assumption.

[Nutt]

Took the plugs out and checked last night. They had some carbon build up around the edges, but all in all, they still looked good. Was hoping to get this checked out this week and possibly fixed by the weekend, but it doesn't seem to be working out since no one has the time to hook it up and check it out. Kinda afraid to keep driving it, which sucks, because I am supposed to be in a tournament this weekend and don't want to further any damage that it may have.

[EuropeanAM]

I would definitely recommend that you have your dealer check this. If you've not found a dealer that is able to get you in... try:

https://www.mercurymarine.com/en/us/find-a-dealer/

[Nutt]

Thank you for your help. I really appreciate it. I will try to find someone to look at it, hopefully this weekend. This sucks.

[Nutt]

Dropped it off at the shop this morning. Wont be able to tell me anything until maybe Tuesday, but they are thinking it may be a dropped cylinder or a problem with the head. Have to tear into it to be sure. Sucks that the motor only has 40 hours and could have an issue like this. Not happy, but at least its under warranty.

[Wildcat Dude]

yep, definitely sucks but at least its under warranty and hopefully it won't be bad.

[1sharphook]

Please let us know what they find thanks.