SHO running 15MPH Slower than usual

[DSkeeter23]

Good evening,

I’ve purchased a 2014 Skeeter TZX190 w/ a Yamaha 150 SHO last June. The boat was running healthy once i brought it home. This season I took it out of hibernation in the beginning of April. (Upstate NY)

I winterized the boat accordingly and had it trickle charging throughout the winter time.
Last season I did hit a top speed of 62 MPH on a clear day mild chop with water temps at 70degrees.

This season with the same load i only reached 48 mph which really has me thinking. I’m basing that off of what my GARMIN UHD 93sv with GT56 transducer is showing me. There’s no bogging or anything noticeably different with how she’s running just the top end speed.

I didn’t really de-winterize the boat because the lower unit oil was changed before storage, a new water/fuel separator was installed, some stabilizer in the gas tank which I burned off already before filling up again. The Spark plugs are the same I didn’t change them this season yet.

This past weekend i took off the propeller thinking maybe i had some fishing line and gunk but it was pretty clean. I re-greased it and put it back together.

I have yet to check the fuel filter this weekend but does anybody else have any clue what the problem can possibly be. I don’t have any alarms sounding but i did realize my Water Pressure Gauge is consistently at 20+ Even at low RPM’s.

any ideas and help would be greatly appreciated !

[bgibson]

I would change plugs (make sure plug wires are secure) and fuel filters. While under the cowling I would check to make sure the throttle body is clear of rags etc. I had a buddy once that had a mechanic put a rag over throttle body to stop rodents.

[mknj671]

If you water pressure gauge is stuck at 20 it sounds like you did not disconnect and purge the water out of the line before storing the boat, it likely froze and will need to be replaced.

Is the motor still idling fine and reaching full RPM when trimmed out? Should be close to 6K if tach is reading correctly, if the motor is coming on plane quickly and running OK otherwise it might be the prop hub failing causing slip. Check obvious things like electrical connections including ground wires and fuel supply but normally those issues cause other types of running problems. If the motor is not reaching full RPM check hotfoot and motor connection and ensure the adjustment is correct, sometimes the bolts do loosen up. Since you changed the main fuel filter did you prime the system again using the bulb? If that large filter has any air in it there is a chance it is causing issues at higher RPM starving the motor for fuel.

[DSkeeter23]

If you water pressure gauge is stuck at 20 it sounds like you did not disconnect and purge the water out of the line before storing the boat, it likely froze and will need to be replaced.

Is the motor still idling fine and reaching full RPM when trimmed out? Should be close to 6K if tach is reading correctly, if the motor is coming on plane quickly and running OK otherwise it might be the prop hub failing causing slip. Check obvious things like electrical connections including ground wires and fuel supply but normally those issues cause other types of running problems. If the motor is not reaching full RPM check hotfoot and motor connection and ensure the adjustment is correct, sometimes the bolts do loosen up. Since you changed the main fuel filter did you prime the system again using the bulb? If that large filter has any air in it there is a chance it is causing issues at higher RPM starving the motor for fuel.

Thanks for the reply!


I actually didn’t disconnect the line an purge it. I let her run for a bit after the last use pre-Winterization. I got a early start this season at the end of March and took her out a handful of times. Of course some unexpected freezing temps moved in so maybe that was the cause of the water line defect.


The motor is idling fine and seems to be coming on plane fairly quickly as usual. I have to check the RPM’S Friday when i take it out an see where they stand. I had Towne Marine remove the hotfoot before i picked her up last year (6’4 it was rough lol)


Since i was short on time in the fall I took it to a marina to get winterized an shrink wrapped. They did change the fuel/water separator and I assumed they topped it off with gasoline before tightening it back up. I might have to give the bulb a few more squeezes to get it running accordingly. Would that get the air out of the system just by priming it ?

[PSM207]

I suspect you are not achieving full throttle.

[mknj671]

Thanks for the reply!


I actually didn’t disconnect the line an purge it. I let her run for a bit after the last use pre-Winterization. I got a early start this season at the end of March and took her out a handful of times. Of course some unexpected freezing temps moved in so maybe that was the cause of the water line defect.


The motor is idling fine and seems to be coming on plane fairly quickly as usual. I have to check the RPM’S Friday when i take it out an see where they stand. I had Towne Marine remove the hotfoot before i picked her up last year (6’4 it was rough lol)


Since i was short on time in the fall I took it to a marina to get winterized an shrink wrapped. They did change the fuel/water separator and I assumed they topped it off with gasoline before tightening it back up. I might have to give the bulb a few more squeezes to get it running accordingly. Would that get the air out of the system just by priming it ?

If it ran fine the first few times out this season and then the issue started it is likely not the fuel filter. You can prime the system with the bulb after changing the 10 micron filter, it does not need to be filled with fuel before reinstalling it. So it was switched back to hand throttle operation from the hot foot? If so I would start there for sure, different length cables and perhaps one of the holding nuts backed off. Take off the motor cowl off and put the motor control all the way forward - the two marks on the throttle body should align. If they don't as someone mentioned you are not achieving full throttle and it needs to be adjusted.

[ThomasD]

Hot foot removed is a dead giveaway. Bet they didn’t check adjustment for full throttle

[DSkeeter23]

Hot foot removed is a dead giveaway. Bet they didn’t check adjustment for full throttle

The hot foot was removed before I brought the boat home after purchasing it. I used it all of last summer, Hitting a top end speed of 63. Starting this season after a long winter the boats clocking in at 48ish. So the hot foot is not the problem cause I never had it on. unless like MKNJ671 stated that maybe one of the holding nuts backed off in the hand throttle.

[bgibson]

Knowing the hotfoot was removed by God knows who at the dealer I would definitely look to make sure you are reaching WOT! Most People just don't do good work anymore, or lack experience.

[DSkeeter23]

Knowing the hotfoot was removed by God knows who at the dealer I would definitely look to make sure you are reaching WOT! Most People just don't do good work anymore, or lack experience.

you got that right, reliable work is hard to find nowadays. Few things for me to check this weekend.

thanks everyone !