525 Merc backfiring
 

Boat ran great all weekend, docked it Saturday night. Sunday morning I took it out, got it planed off no problem. I noticed the Starboard Floscan meter was reading about 20 GPH (I think at 3000 rpm) and the Starboard Floscan was less than 15 GPH (At the same rpm-thought that was odd) then the Starboard motor started backfiring and loosing power. It would idle fine and all gauges looked normal, no alarms. I could put the engine in neutral and get it to backfire just reving it up. Any thoughts?

lean pop?
dirty filters or clogged inlet screen on the low pressure fuel pump?

Kevin,

Did you maybe pick up some bad gas somewhere and block up a fuel filter? First sign of a lean condition is backfire.

Rip/Chris,
The low reading on the FloScan would seem that you could both be correct. I wasn't sure if that would cause it to backfire.

I'll tell 'ya this fuel now breaks down some rubber and I personally think filter element sitting in the filters for 7 months. Not to mention attracts H2o when it sits.
I'm changing all 4 filters before I start the engines for the season. I have them here.

the program is now change them in the spring for these reasons.

after the stereo install that is. :drink:

You may have enough velocity in the speakers to move your boat without even firing up the engines when you get done with that setup! Lookin good.

Kevin,
Your boat sure looked good running Saturday in the poker run. Did you buy any dock gas? I try to stay away from the stuff. Even docks with good intentions and equipment can get water into their lines through condensation, leaks and osmosis.
Nice to meet you and your family.
Regards,
Steve

I fueled up on land before I launched Friday and boat ran great. I refueled on Saturday morning at GH Marina. (90 gallons) That's the fuel I was using during the PR event and it seemed to run OK but that's when I started to notice the Starboard/Port GPH readings were not anywhere close. Could have been the beginning of the problem.

Thanks for the compliment! You had a sweet ride as well. We had a great time and it was nice meeting you too. Have a safe season and hopefully we can hook up again. Maybe I can buy you a drink next time!

Kevin

Kevin,
We're on with the drink for sure:drink: . My friends with the 29' Formula really liked your boat as do I. Sounds like it has a genset and AC? Pretty, fast, and comfortable is the best of all worlds to me.
Simply Kevin, I think you got a bad load of gas. That's the only only thing that changed, and your motor began to act up. I would either pump it out, or add a lot of gas dry and change the water separating fuel filters.
Bad dock gas usually is worse this time of year (sitting for some time due to slow sales, loses octane, gets condesation, etc.). This is not very high tech, but I would remove the filter from the backfiring motor (carefully) and empty it into a Mason jar or large clear water glass. If it has water in it, it will seperate out from the gas and be easily visible.
Regards,
Steve
PS, please feel invited to join us for our MCPA poker run here in Nashvegas on Old hickory Lake August 4th........
www.musiccitypowerboat.com

where is the fuel filter on the 525efi?

If it's like my 575, the water separating filter is right above the belt driven fuel/water pump. There is another one near the distributor on the high pressure EFI line.
Steve

I know where the water seperator is but not the fuel filter.

The white filter above the fuel/water pump is the water separating fuel filter. Fuel goes in and out of the top of this cannister. Since water is heavier than fuel, it should stay to the bottom of the filter/cannister, fuel to the top. It is the also the primary fuel filter. This is the filter Kevin should change.
The 575s have a secondary high pressure filter located above and behind the port valve cover. I am sure the 525 does too, but I am not aware of it's exact location on the motor.
Steve

Very nice boat Kevin. I saw you run by our cabin at WOT with rooster tails and all .. It sounded fantastic. My buddy with the Big cig complimented, And thats saying somthing(staggered 1075's)... I was in the black boat with the flames. Saw you on several occations... will you be coming to our Poker run On the 19th on Kentucky lake?

Evan

Evan,
I saw you going down the river next to GH Marina. I remember pointing your boat out to my wife because I thought that was the one that just got painted this winter. (Wasit?) It looked sweet! Thanks for the compliments and tell your buddy that too! We ran the boat pretty good that day and it performed excellent. Had a great time. I'll check out the calendar for that run and see if we can make it. I have Chicago planned and weekends get chewed up pretty fast right now if I don;t start making commitments-I'm sure you know the feeling. Hope you guys had a good time there. Thanks again.