Sea Buzzard
Cadet
- Joined
- May 3, 2010
- Messages
- 16
I have a 2006 4.3 190hp MerCruiser S/N OW379161. I bought it new in Jan 2006 and it only has 130 hours on it. In 2009 I had it out and over a 6 hour trip it would bog down to about 3800 rpm at WOT and then pick back up. It did this 3 times. I replaced the spark plugs and I didn't have a problem for the next couple times I took it out. Then it would not run at all.
I burnt up a starter in the driveway trying to get it started. After having the starter replaced by the dealer, it ran good for one trip. I get home and try to start it to flush out the salt water and it does not want to run. I thought I had bad gas, so I replaced the fuel/water separator and drained the 40 gallons remaining and filled it with 80 gallons of fresh fuel. Still would not run. Finally I removed the cap and rotor and they had green corrosion. It ran fine the rest of the year. This was last year.
I thought I had solved my problem. In March of this year I filled the boat with fuel, but I thought it had 3/4 of a tank, but it only had 1/4 of a tank. It had set all winter with 20 gallons in a 80 gallon tank. I started the boat in the drive way and it ran fine. In mid-April I put the boat in the water and it ran fine, I did not get to WOT since I had my 4 yr old son with me and there were 2 ft swells in Puget sound. The beginning of May I tried to start the boat in the driveway and it would not run. I pulled the cap and rotor and it had green corrosion again, after only one year. I replaced it.
I put the boat in the water, and it would not come up past 3800-4000 rpm and then it died. WOT is normally 4400-4800. I pulled the spark arrestor off, and after some looking at it, I nursed it back in about 2 miles. I got close to the ramp and it started running OK, I headed back out to go fishing and it would run, but not go above 3800 rpm. After making a few runs of 4-5 miles apiece I headed back.
While I was out, It would bog down when I would bring the throttle up, but it would cough and then come up in rpm. I brought it back home and diconnected the fuel pump and ran the carb dry. I sprayed carb cleaner in the vacuum holes and removed the fuel/water separator, dumped the fuel into a jar and it had some contaminents in it, but no water. I put about 1/2 cup of Seafoam and 1/2 cup of carb cleaner in the new separator and put it on. I put 3 bottles of Heet in the gas tank and finally got it started. Poured some Seafoam down the carb and got it cleaned out. Pulled the plugs and they looked good.
Put it in the water and it ran fine, but would still not go above 3800-4000 rpm. Put it in the water today and it died as soon as I put it in gear and tried to come up on rpm. At first it would rough idle, then would not run at all. I got back to the ramp on the kicker. Got home and checked the plugs, they are good. Cap and rotor are good. Plug wires read out at 1500-1800 ohms. Coil reads about the same. Even on the hose it will backfire when I bring it up on rpm. I eventually got it to 4000 and there was knocking noise. Even at 1500 it would fluctuate between 2000 and 1200. I did notice that the right side barrel of the carb had a better spray pattern than the left at all rpm.
I think I have multiple problems. I don't know why it would run fairly good except for not getting to WOT one day and then not run at all the next day. Spark appears good, fuel appears good. I know this is a long post, but I wanted to give as much info as possible. I'm running out of cheap/easy things to try. I really don't want to pull the carb off and after reading some of the post on here don't think that I need to but I evidently can't figure it out. I would check the timimg, but there is no tab to check it against, there is a metal sticker on the harmonic balancer, but I have no idea how to adjust timing by using that.
I burnt up a starter in the driveway trying to get it started. After having the starter replaced by the dealer, it ran good for one trip. I get home and try to start it to flush out the salt water and it does not want to run. I thought I had bad gas, so I replaced the fuel/water separator and drained the 40 gallons remaining and filled it with 80 gallons of fresh fuel. Still would not run. Finally I removed the cap and rotor and they had green corrosion. It ran fine the rest of the year. This was last year.
I thought I had solved my problem. In March of this year I filled the boat with fuel, but I thought it had 3/4 of a tank, but it only had 1/4 of a tank. It had set all winter with 20 gallons in a 80 gallon tank. I started the boat in the drive way and it ran fine. In mid-April I put the boat in the water and it ran fine, I did not get to WOT since I had my 4 yr old son with me and there were 2 ft swells in Puget sound. The beginning of May I tried to start the boat in the driveway and it would not run. I pulled the cap and rotor and it had green corrosion again, after only one year. I replaced it.
I put the boat in the water, and it would not come up past 3800-4000 rpm and then it died. WOT is normally 4400-4800. I pulled the spark arrestor off, and after some looking at it, I nursed it back in about 2 miles. I got close to the ramp and it started running OK, I headed back out to go fishing and it would run, but not go above 3800 rpm. After making a few runs of 4-5 miles apiece I headed back.
While I was out, It would bog down when I would bring the throttle up, but it would cough and then come up in rpm. I brought it back home and diconnected the fuel pump and ran the carb dry. I sprayed carb cleaner in the vacuum holes and removed the fuel/water separator, dumped the fuel into a jar and it had some contaminents in it, but no water. I put about 1/2 cup of Seafoam and 1/2 cup of carb cleaner in the new separator and put it on. I put 3 bottles of Heet in the gas tank and finally got it started. Poured some Seafoam down the carb and got it cleaned out. Pulled the plugs and they looked good.
Put it in the water and it ran fine, but would still not go above 3800-4000 rpm. Put it in the water today and it died as soon as I put it in gear and tried to come up on rpm. At first it would rough idle, then would not run at all. I got back to the ramp on the kicker. Got home and checked the plugs, they are good. Cap and rotor are good. Plug wires read out at 1500-1800 ohms. Coil reads about the same. Even on the hose it will backfire when I bring it up on rpm. I eventually got it to 4000 and there was knocking noise. Even at 1500 it would fluctuate between 2000 and 1200. I did notice that the right side barrel of the carb had a better spray pattern than the left at all rpm.
I think I have multiple problems. I don't know why it would run fairly good except for not getting to WOT one day and then not run at all the next day. Spark appears good, fuel appears good. I know this is a long post, but I wanted to give as much info as possible. I'm running out of cheap/easy things to try. I really don't want to pull the carb off and after reading some of the post on here don't think that I need to but I evidently can't figure it out. I would check the timimg, but there is no tab to check it against, there is a metal sticker on the harmonic balancer, but I have no idea how to adjust timing by using that.
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