-NOOB WARNING-
Hi, I’ve never posted before but I’ve read and read thru the forums and can’t find my specific issue. I’m sure it’s been answered but I can’t find it.
-NOOB WARNING-
MY BOAT:
1976 Mark Twain Tri-hull open bow.
My Motor:
Mercruiser 120HP 2.5L 4CYL
MY SITUATION:
It starts on the first crank and idles beautifully. After it warms up it starts to rough Idle. This is accompanied by what sounds like a gasping noise coming from the top of my fuel tank(it’s tight so I can’t see up in there to see what’s making the noise)
It sounds kinda like Pshh....Pshh....Pshhh... and sometimes it gets quicker and shorter Psh..Psh..Psh..
and then after a few minutes Of rough idleing ...it dies.
It gasps even if the fuel cap is off.
I even sprayed starter fluid directly into the carb but still won’t fire up. I let it sit for a day or two and it fires right back up and runs fine until it warms up for about an hour or so.
WHAT IV’E DONE SO FAR:
Now she didn’t always run this well. I bought it as a non running project.
When it fired right up I thought I lucked out.
So I Changed the impeller and drive coupler new rear motor mount gear alignment etc etc etc etc... and I took it to the lake.(my first time)
I pulled it off the trailer and left it to idle at the dock while I parked the truck. Like I said it was my first time so doing that all took around 15-20 minutes. I Stepped aboard and noticed the rough idle and then it died.
I got it to start again after about 30 minutes but it just rough idled some more and died. Would not restart. (THANK GOD WE WERE STILL DOCKED!)
I Brought it home and let it sit for a couple of days and it started up fine on the hose for about 20 minutes and then died.
After checking the forums I changed the plugs, wires and coil. Now it runs for 70 minutes and dies. Which makes me think I’m on the right track but the gasping sound makes me wonder if I’m going down the wrong rabbit hole? I Also tried removing fuel fill cap but it still gasps.
And as I mentioned I also sprayed some starter fluid directly into the carb during the issue with no change.
Also, it’s cooling perfectly right around 138 degrees. Compression is 125 using just the battery to crank with plugs out and with the throttle wide open. Can’t find the choke.(automatic?)
I know it’s not great but it’s not dead either all cylinders are within a pound or so of 125psi.
Now I’m not a mechanic my boat just wants me to be one and I can’t seem to stop myself from fixing it. So far it’s been like a cruel one way relationship and while Im happy to announce that I did get to spend the whole summer on my boat I have to admit that only 30 minutes of that was in the water, the rest has been in my driveway. Still hoping to just get one ride out of it before I pack it up for the winter. Any help is much appreciated!!!
THANKS!
Hi, I’ve never posted before but I’ve read and read thru the forums and can’t find my specific issue. I’m sure it’s been answered but I can’t find it.
-NOOB WARNING-
MY BOAT:
1976 Mark Twain Tri-hull open bow.
My Motor:
Mercruiser 120HP 2.5L 4CYL
MY SITUATION:
It starts on the first crank and idles beautifully. After it warms up it starts to rough Idle. This is accompanied by what sounds like a gasping noise coming from the top of my fuel tank(it’s tight so I can’t see up in there to see what’s making the noise)
It sounds kinda like Pshh....Pshh....Pshhh... and sometimes it gets quicker and shorter Psh..Psh..Psh..
and then after a few minutes Of rough idleing ...it dies.
It gasps even if the fuel cap is off.
I even sprayed starter fluid directly into the carb but still won’t fire up. I let it sit for a day or two and it fires right back up and runs fine until it warms up for about an hour or so.
WHAT IV’E DONE SO FAR:
Now she didn’t always run this well. I bought it as a non running project.
When it fired right up I thought I lucked out.
So I Changed the impeller and drive coupler new rear motor mount gear alignment etc etc etc etc... and I took it to the lake.(my first time)
I pulled it off the trailer and left it to idle at the dock while I parked the truck. Like I said it was my first time so doing that all took around 15-20 minutes. I Stepped aboard and noticed the rough idle and then it died.
I got it to start again after about 30 minutes but it just rough idled some more and died. Would not restart. (THANK GOD WE WERE STILL DOCKED!)
I Brought it home and let it sit for a couple of days and it started up fine on the hose for about 20 minutes and then died.
After checking the forums I changed the plugs, wires and coil. Now it runs for 70 minutes and dies. Which makes me think I’m on the right track but the gasping sound makes me wonder if I’m going down the wrong rabbit hole? I Also tried removing fuel fill cap but it still gasps.
And as I mentioned I also sprayed some starter fluid directly into the carb during the issue with no change.
Also, it’s cooling perfectly right around 138 degrees. Compression is 125 using just the battery to crank with plugs out and with the throttle wide open. Can’t find the choke.(automatic?)
I know it’s not great but it’s not dead either all cylinders are within a pound or so of 125psi.
Now I’m not a mechanic my boat just wants me to be one and I can’t seem to stop myself from fixing it. So far it’s been like a cruel one way relationship and while Im happy to announce that I did get to spend the whole summer on my boat I have to admit that only 30 minutes of that was in the water, the rest has been in my driveway. Still hoping to just get one ride out of it before I pack it up for the winter. Any help is much appreciated!!!
THANKS!