250 Pro XS Optimax surging when cold

[BigCountryx]

I've got a 250 Pro XS Opti (SN: 2B090714) that surges on the first time getting on plane each trip. When I push the throttle rpms rise like normal but just before it breaks over, the rpm drops to idle for a second and then start to increase again without ever changing the throttle position. It will do this several times, then eventually, it will build enough speed to get on plane. Once it does that, it operates fine the rest of the day. I did have a repeat issue once during the day, but it had sat for 5 hrs before restarting it. Again, once on plane, no more issues, I can slow down for idle zones, other boats, even kill and restart it without any more issues. The battery is a 1000 CCA NAPA battery that is only a year old. I have always maintained a charge, but I do notice that the voltage seems to drop quicker than I think it should when using power poles, trim, jackplate etc. When the engine isn't running. Could a faulty battery cause issues like this?

[lpugh]

Are you pumping the primer bulb up till firm. If not try this first and report back

[EuropeanAM]

+1

To answer your other question- yes, a battery/voltage problem CAN cause this. You might also want to check the tensioner to make sure it's capable of at least 70 lbs/in (set a lbs/in torque wrench to 70, it should click BEFORE the tensioner arm reaches the end of it's travel). Good idea to inspect the belt while you're in there.

One item we saw on a few of these was in the VST, screws and retainer for low pressure fuel pump may not be secured fully, sometimes presented only when cold.

[BigCountryx]

No, I'm not pumping the bulb. Never have on this motor, but I will surely try that. I will check that tensioner and the VST as well. Thanks guys.

[JOE54]

report back please

[BigCountryx]

Not sure it's the smoking gun, but found this when replacing my fuel line and bulb. Doesnt look right to me. I just went ahead and ordered everything Don recommended for the yearly maintenance along with the fuel lines, rebuilding the pulse pump (that kit was on backorder, so it took 3 weeks to come in) and cleaning out the vst. The fuel filter wasn't in the package for some reason though, ill have to call and figure that one out, so I haven't water tested it yet.

20240410_200610.jpg

[JOE54]

huh that will sho cause it right there , good ol folded liner , lucky didnt loose a powerhead , real lucky

[Savage]

^^^^^This^^^^^

[BigCountryx]

My motor is back in action, running great. I'm sure it could have been something else, but all signs point toward the collapsing hose liner being the issue. Along with the hose and bulb replacement, I also rebuilt the pulse pump, changed the fuel filter, cleaned out the VST, inspected both electric pumps, changed the spark plugs as well as all the normal yearly service items. (btw, be sure the wiring for the low pressure pump is pushed on tightly before putting the top back on the VST... I'm an idiot) But, everything was clean and all looked just like it should have, so I really don't think anything else was a contributing factor. Thanks for the help.

[JOE54]

Not sure it's the smoking gun, but found this when replacing my fuel line and bulb. Doesnt look right to me.

20240410_200610.jpg

smokin

[EuropeanAM]

gun