Logo
FULL SITE MENU

4.3l tbi need help!!!

1

1marc1

Contributing Member
Hey posted on here previously. I had issues with my 4.3L TBI Merc. This problem seems to start just instantly one day after a really quick shut down in the water. I was having problems with the boat starting and idling, it was running extremely rich and smoking when it did start, i was having problems planing the boat out of water.....but once planed had no problem getting 50MPH out of it (on the speedo guage). So initially we thought it was the fuel regulator due to the sluggishness out of the hole, it not wanting to start and run on low idle......because it was overfueling. Made sense to us. I have the cool fuel system on the boat but we decided to by pass the existing regulator and put on an external after market regulator on just to see if the regulator was the problem. There was minimal improvement it seemed to run a little better, it quit smoking but again in the water.....wouldn't idle, and wasn't easy to start but once able to start it was difficult to plane out but still was able to get good top end once planed. So after so much aggrevation trying to think what the hell the problem was and just trying one thing after another i broke down and decided to take to one of the few boat places i have in my area. I explained all the details to their service manger what the problems were etc etc......i left the boat in what i thought were capable hands. A few weeks later the service manager calls me back and says my whole cool fuel system isn't working properly. He says Its over fueling and dumping fuel in my oil pan, (no duh) and then told me i would need a new fuel pump and regulator.......this was confusing to me because the fuel pump obviously is working if its pumping more fuel out than it should so i didn't know why i needed a fuel pump......figured maybe the boat just needed the factory regulator but....whatever. He told me this was my problem so i went with it hoping he knew something more than me. We waited 2 months for this fuel pump to come in......summer is obviously over now in canada sooooo the duration of this "fix" already has me mad enough but the service manager calls me today.....to tell me that they installed the new fuel pump etc but the boat is still running no different. Then goes on to tell me that i don't have compression on my port side front cylinder and no compression on my starboard side rear cylinder.......and then also expects me to pay for the parts and labor on the fuel system that obviously didn't need fixing. So the one thing that i do know is, is that i got severely ripped off by a bunch of "part changers" but now they actually determined a big part of why my boat wasn't running correctly. Sooooo does anyone have any idea what would cause this lack of compression on those 2 cylinder? Could my rings be worn that much? A stuck valve??
 
Yeah im yanking the boat from them this weekend. Popping the heads off and going to take a look. I know the head gaskets are fine. Just confused on why all of a sudden my boat goes from good to having no compression on 2 cylinders. And why those 2 cylinders would have no compression!? Is this a common thing? I barely had 20 minutes on the engine after winterization and then just goes for ****........the remainder of the summer was a write off trying to fix it myself and then wasting my time and money at the dealership.
 
1marc1 said:
Yeah im yanking the boat from them this weekend. Popping the heads off and going to take a look. I know the head gaskets are fine. Just confused on why all of a sudden my boat goes from good to having no compression on 2 cylinders. And why those 2 cylinders would have no compression!? Is this a common thing? I barely had 20 minutes on the engine after winterization and then just goes for ****........the remainder of the summer was a write off trying to fix it myself and then wasting my time and money at the dealership.
Click to expand...

Ayuh,.... Do a compression test, 'n more importantly, a leak down test to see where the compression is goin'...

Once ya pull the heads, yer done disgnosin'...
 
Did wet and dry test, still nothing on both. Got one head off, and my cylinder wall is scored a little bit along the top, but smooths back out as it goes down. No marks of any type to the top of my piston and my head appears to look perfectly fine!?






bondo said:
Ayuh,.... Do a compression test, 'n more importantly, a leak down test to see where the compression is goin'...

Once ya pull the heads, yer done disgnosin'...
Click to expand...
 
Try putting in a new coolant temperature sensor. If it's bad, it can cause the engine to run extremely rich.
Bert
 
Back
Top