Hi all, looking for help! I've down a lot of searching but still can't narrow this down. I've got a mid 90's Sea ray with a 4.3 Mercruiser. The boat has run flawlessly for the 4 years I've had it. Last season, it still ran great, but would not restart after running awhile. After sitting, it would start and again run perfectly. I thought vapor lock, but tried all the tricks to cool it down before turning off and didn't seem to help.
So, thought flooding, even though it didn't real seem like there was excess fuel flowing into the carb. And the WOT start trick doesn't work.
My plan was to rebuild the carb over the winter, but hasn't happened yet! I ran some Seafoam through the carb in the driveway and all seemed to be working well, so took it out for a spring day with the family.
After about 15 mins of cruising at about 2900 RPM, there was a huge backfire and it died. Wouldn't restart, or even fire. Floated around awhile and it eventually would fire, but not start. 10-15 mins of this then it restarted, but would not rev above 2500 under load. Limped back towards the dock. Died 4 or 5 more times limping back. repeated the above procedure and made it back eventually.
So, it's back in the driveway, but I don't know where to start. And here's the embarrassing part: it's pretty low on oil, didn't check it before heading out!
Would low oil cause this? I'll change the oil of course before heading out, but I'm sure it will run fine in the driveway again, so want to get to the root of the problem.
There were never any alarms and the oil pressure gauge read fine. It seems to me that the pressure sensor just leads to the gauge, so don't think there is a safety shut off. I have a mechanical fuel pump, so don't know what the shut off would do?
There is an alarm if you leave the key on too long while not running, so I think it works.
When it won't start there is fuel squirting in when you push the throttle. There is 12v to the coil with the key on, and power leaving the distributor while cranking. But I wasn't able to test while floating around when it wouldn't start.
Any help greatly appreciated!
Jason
So, thought flooding, even though it didn't real seem like there was excess fuel flowing into the carb. And the WOT start trick doesn't work.
My plan was to rebuild the carb over the winter, but hasn't happened yet! I ran some Seafoam through the carb in the driveway and all seemed to be working well, so took it out for a spring day with the family.
After about 15 mins of cruising at about 2900 RPM, there was a huge backfire and it died. Wouldn't restart, or even fire. Floated around awhile and it eventually would fire, but not start. 10-15 mins of this then it restarted, but would not rev above 2500 under load. Limped back towards the dock. Died 4 or 5 more times limping back. repeated the above procedure and made it back eventually.
So, it's back in the driveway, but I don't know where to start. And here's the embarrassing part: it's pretty low on oil, didn't check it before heading out!
Would low oil cause this? I'll change the oil of course before heading out, but I'm sure it will run fine in the driveway again, so want to get to the root of the problem.
There were never any alarms and the oil pressure gauge read fine. It seems to me that the pressure sensor just leads to the gauge, so don't think there is a safety shut off. I have a mechanical fuel pump, so don't know what the shut off would do?
There is an alarm if you leave the key on too long while not running, so I think it works.
When it won't start there is fuel squirting in when you push the throttle. There is 12v to the coil with the key on, and power leaving the distributor while cranking. But I wasn't able to test while floating around when it wouldn't start.
Any help greatly appreciated!
Jason
