250xb rough idle can’t get out of the hole.

[soloman]

Serial OT652622
Kind of a long story lost my lower unit about a month and a half ago. While the boat was down I had the vst and injectors serviced also new set of plugs seemed like a good time while waiting for the lower. Had the new lower installed and went out to the lake and the boat started up idle for a bit “rough” and died pumped the primer bulb up fired it back up and it idled okay got out out the no wake and it came out of the hole but rough and slow boat is normally a rocket out of the hole. Got it to the mechanic and we messed with it top two cylinders and center starboard if you unhooked the plug wire didn’t make much of a difference on idle. Checked spark with a tester and it’s nice and strong. Injectors were just serviced and flowed great. Pulled the intake back and watched the spray pattern those three cylinders weren’t spray nearly as strong as the lower ones. So he pulled the injectors back out and had them retested and checked they are all fine. Checked compression it’s almost dead nuts 120pai across the board + or - 2 psi. We came to the conclusion that it probably had a hurt computer I got a replacement computer and harness of a known good running engine and it has the same exact symptoms. Checked fuel pressure while running. Video attached. I can’t find my manual but if memory serves me correct it should be 43psi. Any ideas on what to check or where to go from here getting frustrated with this dang engine. Harness going through the intake into the injectors possibly orrr?? I’m lost

https://youtube.com/shorts/JKycOQ-OSkY?feature=share

[Bob G.]

Was the engine running fine before the lower unit failed?

[JOE54]

^^^^^+100 , QL77CC plugs ???????

[soloman]

Was the engine running fine before the lower unit failed?

Yes engine was running great. It’s always had a little stumble at low rpm “going through a no wake zone” that nobody could figure out had it at 3 different shops here. I ended up making new power and ground cables from the engine into the boat and that solved 70% of my problems. Went out and tested it yesterday and it’s got a pretty bad noise now has anyone ever hurt a power head when a lower fails? Link to video below.

https://youtube.com/shorts/-foz86hNTS4?feature=share
and yes plugs were ordered from don per the serial.

[soloman]

Double post

[JOE54]

pretty rare occurrence for it to , now that you have some injectors that are not lets say up to par you may have a powerhead problem resulting from that , note;;;; i didnt say failure of one .... good luck JOE

[soloman]

pretty rare occurrence for it to , now that you have some injectors that are not lets say up to par you may have a powerhead problem resulting from that , note;;;; i didnt say failure of one .... good luck JOE

The injectors are up to par the flow even and run great just not on the engine I believe I have that one solved though ran a new power and ground to the engine from the battery noticed some white corrosion on them.

[JOE54]

lake test to confirm

[soloman]

lake test to confirm

Went out to the lake and that noise is what I found. Idles smooth comes out of the hole good again but I shut it down pretty quick because of that noise

[JOE54]

time for some inspections compression test and borescope , gearcase inspection of fluid and or remove bearing carrier for visual