carb rebuild?

boatman37

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So fired the boat up the other day in the driveway and it ran for about 2 minutes and shut off. Been having fuel issues so want to rebuild the carb next but can't find any numbers on the carb other than a sticker that says SAE J1223 Marine. The boat is a 2006 Crownline 250CR with a 5.7 2 bbl carbed motor with TKS (turnkey start). The boat is not fuel injected but with the TKS you can start it without touching the throttle.

Here is the number on the spark arrestor> 0W383495. It also says 'FAMILY 5M9XM05.72VC. Date of Manufacture is Oct 2005

any idea what carb kit I need? I looked all over for any stampings in the carb and don't see any
 

Scott Danforth

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Carb kit listed in parts breakdown. Use your serial number on the mercury marine site
 

QBhoy

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Although I haven’t been around a V6 or v8 tks engine at all...I’ve been around a few 3.0 tks.
Starting without throttle on these in reality isn’t something I’ve seen them do much at all. The enrichment gizmo usually seems to mess things up. Not sure if yours has it. Very likely does and this is the issue. Google it and have a look at yours. Before you go to the trouble with carb. Good luck.
 

boatman37

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i tried pumping the throttle too. when i pump it it will stay running about long enough to burn the fuel that pumped in. as soon as i add throttle it will stall too. holding your hand over the carb it will idle. not sure what else it can be?
 

boatman37

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So siphoned 20 gallons of fuel out off the bottom of the tank a couple months ago and put the boat in and had it out twice with no issues, So tried it again today.

Went out today and putsied out of the no wake zone about 100 yards to the Ohio river then got up on plane. Ran about 1/2 mile up river on plane then came back down river about 1 mile then turned around and went to our anchor spot. When I backed off the throttle it stalled and wouldn't start. Dropped the anchor and pulled the fuel separator and dumped it in a container and it was about 50% bad fuel (separated). Had a new separator in the cabinet so put it on. After a couple hours on the hook we started it up and had to keep the RPM up for a few minutes to clear the bad fuel from the carb. After that I dropped it to idle and it sat there fine for about 5 minutes. Took off and got up on plane and all was good. Got the to entrance of our river and backed it down to about 1000 RPM's and it died again. Made it over to an old dock and tied up there and pulled the new separator and dumped it in a container. Fuel looked good. Put it back on and started it. It wouldn't start unless I pumped the throttle and would only run over about 2000 RPM. Anything under that and it stalled. We were only 50 yards from our slip so a dock neighbor came and towed us in.




So remember my boat is a 2006 Crownline but it has a 5.7 Merc 2 bbl with TKS. It has an electric fuel pump and you don't have to pump it before turning the key. It is NOT fuel injected





Any ideas? My first thought is more bad fuel but when I pulled that new separator after about 1/2 mile that fuel looked good. My thoughts are to siphon the remaining 45-50 gallons and put it in a 55 gallon drum for now then fill it with new fresh fuel and a new separator. If it still does it then I have 50 gallons of fuel to use as needed and look for a different issue?
 

Bondo

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Put it back on and started it. It wouldn't start unless I pumped the throttle and would only run over about 2000 RPM. Anything under that and it stalled.
Any ideas? My first thought is more bad fuel but when I pulled that new separator after about 1/2 mile that fuel looked good.

Ayuh,..... It's my Guess that some of the crud made it into the carb, 'n is the root of yer problem,....

Btw,.... The bad crap lives at the bottom of the tank, no reason to empty it,.....
Suck the crap out from the bottom,....
 

boatman37

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Yeah I siphoned it from the bottom. I have a West Marine pump style oil siphoning tank for changing oil and I put the tube at the bottom and pump away. It only holds a little over a gallon so takes alot of pumping and dumping...lol.

I still haven't rebuilt the carb. It ran fine after I siphoned that 20 gallons out a few weeks back
 

Rick Stephens

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Any chance there is a source for rainwater to get in the tank? Hard to believe you clean out your tank and a few weeks later find separated fuel water in the filter. Might check caps and vents and make sure you don't have a water importing leak.
 

boatman37

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i didn't drain the whole tank last time. just siphoned it off the bottom until just good fuel came out but i plan to siphon it dry this time. but you do bring up a good point. i checked my filler cap last time and there was no o-ring and didn't notice a place for one but will cheavk again tonight. maybe it is missing and that is how it is getting in?
 

boatman37

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No o-ring on these. Dock neighbor has the exact same boat and he told me his does not have one and he pulled it to verify it. Another guy at the marina said it wouldn't have one.

So we get there tonight with intentions of siphoning fuel till it's empty. Siphoned 5 gallons and it all looked good. Decided to try it and it started right up and idled. Let it run about 10 minutes and it was fine so shut it off. Temp got to about 150. Waited about 10 minutes and tried again but it wouldn't run. Took the inline filter out of the carb and it looked good and I was able to blow through it easily. Put it back together and it started right up then stalled after a few minutes. Took that filter out again and left it out. At that point it would start but barely idle and die as soon as I give it a little gas.

I pulled the gas cap to see if maybe the vent line was plugged but that didn't change anything


Started thinking maybe time to rebuild the carb?
 

Scott06

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Yes time to rebuikd the carb, and make sure nothing but clean gas is being supplied to it
 

boatman37

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Well guess there is supposed to be an o-ring. mine does not have one and didn't see anywhere where it would sit. Going to have to get one of those but that still doesn't fix the issue of it not running now. The 5 gallons I pulled out looks perfectly fine and I siphoned it off the bottom so if there was any moisture it should have picked at least some up.

What is the deal with separators? Once they are waterlogged can they be dumped and put back on or are they bad after that? I'm thinking if I replace the separator (that has about 1/4 mile of use on it and looked to be good when I pulled it back off) and rebuilt the carb I'm thinking it will be good to go?

Thoughts?

 

boatman37

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So went down today and bought another new separator on the way there. Pulled the old separator and it looked good. It was only on for about 1/4 mile before it died. Put the inline filter back in too. Started it up and it sputtered and barely idled and would die as soon as I touched the throttle. Step-son looked down into the carb and could see water droplets on the floor of the intake. We put the new separator on and sprayed a little starting fluid in and it started right up and idled at the dock for 45 minutes before I shut it off. It started right back up and would handle higher RPM's just fine. Very weird...lol. Seems that new separator I put on Thursday went bad after 1/4 mile?
 

boatman37

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ordered a couple of o-rings for the fuel cap. went to the marina today and the boat started right up and idled fine. i rocked it back and forth for a few minutes to move any water around that might be in the fuel or carb and still good. revved up good. let it run about 10 minutes until it started raining hard so closed it back up. but wondering if when that first separator was 50% water that water got into the carb and engine. so the new separator didn't fix it but after running it long enough it burned off the water?
 

boatman37

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So they o-rings came today and I put one on so hopefully that helps. Haven't had the boat out since July 4th when we had to be towed back in but been starting it up in the slip and it has ran fine. Also been siphoning the fuel out. Down to about 17 gallons left and so far all fuel I have pulled has looked good but want to be sure and start fresh. Haven't rebuilt the carb and not sure I will. Will wait and see how it runs after I get all the fuel out and change the separator.
 

achris

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When you siphon fuel out, what attitude is the boat at? If it's sitting in the water, then it's likely any water in the tank is running forward, to the lowest point, and when you're cruising, it's running back and hitting the pickup... Worth thinking about.

Also, with it sometimes running, sometimes not, sometimes will only run on the main jet and not on the idle/off idle circuits does suggest some debris moving around in the carburetor.

Chris...
 

boatman37

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I had thought about the low point of the tank. I was siphoning from the back right at the pickup hose but have a port near the front of the tank where my sending unit is. I was planning on siphoning as much as I can from the back of the tank then pull the sending unit and siphon whatever I can from there. Between the two I should be able to get 99% of the fuel.

As far as the carb, I'm thinking it might be ok but will see once all the fuel is out and fresh fuel in. The way the weather is we may not get back out this year...lol. Only been out 3 times this year and it stormed pretty bad the last couple days. I hear the river is full of debris so not likely to get out this weekend either.

If I get all this old fuel out and still have any issues then a carb rebuild will be next but I think it will be ok. Hoping to get the rest of the fuel out today.
 

boatman37

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So got the o-ring on Thursday and siphoned all the remaining fuel Friday. Yesterday I put 24 gallons of ethanol free 87 octane and a bottle of Sea Foam. Boat idled fine at the dock.
Started it today and warmed it up then headed out. Ran good through the no wake, got up on plane, then about 1/4 to 1/2 mile later it started to sputter. I backed it down and turned around. It was running about 2500 RPM but sputtering. It did take off once then start sputtering again. I tried going WOT and it bogged worse. It seemed to get slightly better as I pulled the throttle back. I pulled it back to idle and it stayed running so tried to go into my slip. Went the 100 or so yards of no wake to our marina then as I pulled up to our slip it stalled. Luckily I had gotten close enough a dock neighbor was able to grab us and get us in.




Pulled the filter/separator and emptied out the contents and it was fine. Put it back on and still no luck. Ended up pulling the carb off and bringing it home. Plan to order a kit tonight and rebuild it.





The only other things I can think of is vapor lock, the hose from the tank to the filter is getting sucked closed, or the electric fuel pump going. I really don't think it i any of those as it runs fine for awhile then acts up. In all of my years of racing I have only ever seen vapor lock a couple of times so doubt it is that. The fuel hose would probably be a constant issue and fuel pump not real sure if it might be good for awhile then act up?

Trying to identify anything that could possibly be causing this issue to figure it out. Definitely feels like fuel related. It is also possible the filter/separator is getting plugged but hard to believe the last one plugged up in 1/4 mile (maybe 10 minutes of running).


Engine ID is 0w383495

My carb doesn't have a choke. It's a TKS (turn key start). It has an electric solenoid that I think enrichens the carb at cold start. https://www.mercruiserparts.com/bam/subassembly/31841/11741/80

Here is a link to the carb style I have >
0.jpg
 

boatman37

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Got the carb kit today so tore into it. I have rebuilt dozens of carbs and have never seen one that looked like this inside. Any ideas what these tiny tan granules are and what caused them? It is sand. It is soft. They are on the float and in the float bowl on the floor and the sidewalls.

 
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