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Message |
    
bowhuntrrl
Member
Username: bowhuntrrl
Post Number: 48
Registered: 05-2007
| | Posted on Wednesday, April 23, 2008 - 12:30 pm: | 
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I bought a boat late last season, it had been sitting for 4-5 years. I went through the whole darn engine. I rebuilt the carbs, replaced the fuel pump diaphragm and o rings, replaced the plugs, replaced the fuel filters (engine and separator), checked the timing, cleaned the oil tank and put in new oil.
The engine starts and runs great. I can idle on the lake all day, or run at lower rpm. Once I crank it up to WOT, the boat runs about 5 minutes before it starts to die. If I pump the bulb, it takes off again. I've double checked the fuel pump and see no problems with it. I was told that the engine connector fitting can leak air, so I removed it from the system by using a double sided brass fuel barb and hose clamps. I also removed the boats in-hull fuel tank by hooking an external tank directly to the engine (bypassing the separator. It still does it. I really need to get a handle on this since the season is almost here in Massachusetts.
I know it's a fuel supply problem, I just can't figure out what it is. The only thing left is to replace the bulb. Does that seem logical or whatever other suggestion would anyone make??? This one has me baffled.Thanks. |
ikia
Visitor
| | Posted on Wednesday, April 23, 2008 - 02:35 pm: |
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Compression test is required before doing any more work--- it is always the first thing to do! |
Andy Woodhouse
Member
Username: jafa39
Post Number: 44
Registered: 04-2008
| | Posted on Wednesday, April 23, 2008 - 05:20 pm: |
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I had a bulb go sick on me once but that one sucked flat due to the fuel line collapsing, try borrowing a known OK fuel line and running her again, if the line collapses (like mine did) it will be sucked closed and pumping the bulb will push fuel through it and open the line again.
With mine it collapsed between tank and bulb so pumping didn't work.
If the fuel line had been sitting for 5 years with fuel in it may have rotted. |
Stanley Rube
Member
Username: srube2
Post Number: 9
Registered: 07-2007
| | Posted on Wednesday, April 23, 2008 - 07:11 pm: |
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You may want to check the pickup inside the fuel tank. try a friends tank and fuelline and see if that works. I think you have a clogged pickup screen |
Richard
Member
Username: mailman
Post Number: 8
Registered: 08-2003
| | Posted on Wednesday, April 23, 2008 - 08:54 pm: |
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Same thing happened to me. Engine ran nice at idle, then I would get up on plane, then would bog down. Had someone squeeze the bulb and it ran great. My problem was when I put the fuel lines back on the carbs, a tiny, tiny piece of the fuel hose was in one of the carbs. It was the size of a tip of a needle. That cleared up my problem. 87 DT 140 |
JUST-IN-TIME
Senior Member
Username: justintime
Post Number: 3811
Registered: 09-2006
| | Posted on Thursday, April 24, 2008 - 10:00 am: |
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run a fuel pressure/vacuum test
then a spark test
u might have set the carbs too lean |
bowhuntrrl
Member
Username: bowhuntrrl
Post Number: 49
Registered: 05-2007
| | Posted on Thursday, April 24, 2008 - 12:53 pm: |
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The engine has good compression, 135-138 across the board. I have the carb set according to the manual
1 1/2-1 3/4 on the idle jets. What do I need for the fuel pressure /vac test, a vacuum gauge, a fuel pressure gauge , or both ??? How a bout the spark test , what's needed for that ???
My thought was that if I pump the bulb and it takes off that it must be a fuel delivery related problem. That's why I took the original fuel tank and lines completely out of the equation. I'm going to buy a new hose and line to test that theory. Beyond that, I really don't know what to try. |
Richard
Member
Username: mailman
Post Number: 9
Registered: 08-2003
| | Posted on Thursday, April 24, 2008 - 01:56 pm: |
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Check the carbs again to see if there is any crap in the bowls. |
JUST-IN-TIME
Senior Member
Username: justintime
Post Number: 3856
Registered: 09-2006
| | Posted on Thursday, April 24, 2008 - 05:52 pm: |
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check spark to see if they all spark
u can get a vacuum/pressure gauge |
Darren Cook
Member
Username: dcook
Post Number: 5
Registered: 02-2008
| | Posted on Sunday, April 27, 2008 - 10:50 pm: |
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Hi,
Sounds to me like it is drawing vacuum in the tank - is your tank breathing OK ? it might have enough ventilation to service the motor at low RPM but not enough to draw fuel at high RPM ? |
bowhuntrrl
Member
Username: bowhuntrrl
Post Number: 50
Registered: 05-2007
| | Posted on Monday, April 28, 2008 - 12:43 am: |
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Getting spark on all 3 cylinders
Carb bowls are spotless.
Temporarily using a portable tank as a diagnostic tool (eliminate the boat's built in tank). |
Andy Woodhouse
Member
Username: jafa39
Post Number: 46
Registered: 04-2008
| | Posted on Monday, April 28, 2008 - 05:18 am: |
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Keep us posted.... |
JUST-IN-TIME
Senior Member
Username: justintime
Post Number: 3910
Registered: 09-2006
| | Posted on Monday, April 28, 2008 - 12:18 pm: |
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carb bowls spotless, means nothing!!!
you need to pull the jets off and clean right |
bowhuntrrl
Member
Username: bowhuntrrl
Post Number: 53
Registered: 05-2007
| | Posted on Wednesday, April 30, 2008 - 02:11 am: |
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Just in time, I already rebuilt the carbs and still have the problem !!! The boat runs great except after 5 minutes at full throttle, at which time it starts to run out of fuel. I then pump the bulb and it takes off. The carbs were fully disassembled and cleaned, floats checked and adjusted, carbs synched, and timing and idle set. I'm getting 5300 rpm WOT and plenty of smooth power, it just seems to run out of fuel after 5 minutes at high speed.
Please go back and read the original post if anyone has questions, there's plenty of info there about what I have or haven't done. |
JUST-IN-TIME
Senior Member
Username: justintime
Post Number: 3953
Registered: 09-2006
| | Posted on Wednesday, April 30, 2008 - 08:09 pm: |
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either fuel pump or stuck anti-syphon valve
maybe a restriction in the fuel line
hows the filter??? |
Gerald W. Nunnery
New member
Username: reestarheels
Post Number: 1
Registered: 05-2008
| | Posted on Saturday, May 03, 2008 - 08:32 pm: |
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i think you are getting air , i would check all fuel line conections and lines between the carbs.The ones from carb to carb. |
bowhuntrrl
Member
Username: bowhuntrrl
Post Number: 54
Registered: 05-2007
| | Posted on Thursday, May 29, 2008 - 12:17 am: |
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Just an update. I've been too busy to work on it lately. My house needs work, boat takes a back seat. I did buy a fuel pressure/vacuum gauge to test it and also a new bulb/line assembly. I hope that in the next few weeks that I will be able to spend some time on it. I'll let you all know what my testing turns up. One question: Where's the anti siphon valve ?? I didn't see anything about it in the manual ??? |
JUST-IN-TIME
Senior Member
Username: justintime
Post Number: 4269
Registered: 09-2006
| | Posted on Thursday, May 29, 2008 - 12:34 am: |
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let us know |
espen altmann
New member
Username: espen22
Post Number: 2
Registered: 06-2008
| | Posted on Tuesday, June 10, 2008 - 06:51 am: |
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HEY Check the valve between the upper and lower cylinder, if it faults, the fuel pump wont work optimal... it is located on the right side and is fitted with a small red hose..... |
bowhuntrrl
Member
Username: bowhuntrrl
Post Number: 57
Registered: 05-2007
| | Posted on Friday, June 20, 2008 - 11:11 pm: |
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What valve might that be ??? Is it on the starboard side, near the carbs or somewhere else?? I might finally get to work on it a bit this coming week. Unfortunately, I can't find the manual I bought for it last season. |
