Newbie please help

J

Justrunit

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Aug 6, 2011
Messages
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I have a t 1998 crownline with a 5.7 2 barrel carb, been running fine 5000rpm and 47 mph with a 17 4 blade prop, since last fill up will not run but 4000rpm and 38 mph changed all filters and cleaned line and carb new cap and rotor please any help at this point will be a plus thanks in advance
 
vaporvette

vaporvette

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May 2, 2011
Messages
14
Re: Newbie please help

running at 5k for a period of time can damage some engines.I would start with a compression test and then a volume test on the fuel pump(which may only be a problem when hot)
 
J

Justrunit

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Joined
Aug 6, 2011
Messages
7
Re: Newbie please help

I have not run the motor much at all at 5000rpm I have been a Drag racer for years build my own motor this has stumped me went to river the other day when this started we was going down river 4000rpm at 38 then all of a sudden took off like a bat out of hell run for a 200 yards then went back down to 4000 also had prop check this boat has a 1.62 alpha one lower unit
 
J

Justrunit

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Joined
Aug 6, 2011
Messages
7
Re: Newbie please help

Does anybody any clue what this might could be driving me nuts.
 
J

Justrunit

Cadet
Joined
Aug 6, 2011
Messages
7
Re: Newbie please help

I have had the carb totally cleaned and all filter also installed a gauge the pressure is fine.
 
J

Justrunit

Cadet
Joined
Aug 6, 2011
Messages
7
Re: Newbie please help

There are two things that was different got fuel different, and wife flipped kill switch tried to crank several times before she told me. Boat has not run right since about to drive me nuts
 
J

John_S

Rear Admiral
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Jun 21, 2004
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4,269
Re: Newbie please help

Did you find anything in the water sep filter?

Is this a vortec or standard head 2brl 5.7L?
 
J

Justrunit

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Joined
Aug 6, 2011
Messages
7
Re: Newbie please help

No nothing in filter, pulled a fuel sample to check for water today no bubbles, When we was in the river last one time and only one time the boat cut loose and run great for about 200 yards then went back to 4000 rpm, I dont know anything will be helpful at this point. This is a standard 350 5.7 with 2 barrell carb. 1998 Crownline 202br
 
J

John_S

Rear Admiral
Joined
Jun 21, 2004
Messages
4,269
Re: Newbie please help

Justrunit said:
No nothing in filter, pulled a fuel sample to check for water today no bubbles, When we was in the river last one time and only one time the boat cut loose and run great for about 200 yards then went back to 4000 rpm, I dont know anything will be helpful at this point. This is a standard 350 5.7 with 2 barrell carb. 1998 Crownline 202br
Click to expand...

Check your total advance at 2k, 3k, 4K, rpms. Check connections related to T5 icm. When my icm went, it was erratic for a while. The advance timing wuld go to a point and stop. Every once in a while it would "kick in" and get full advance. The icm looks like a solid piece of silicon, but actually has a silicone sealed cover, and water can get in there. There is goop over the circuitry to protect it, but still had issues. I ended up changing icm and the problem went away. I went with the newer retrofit kit which includes new harness connectors. It is expensive, so you want to make sure you are having a timing advance issue.

http://forums.iboats.com/showthread.php?t=349441
 
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