1997 SEARAY Backfiring

[derrick.w.wagner]

Just bought a 1997 SEARAY.

Problem: My engine starts backfiring slightly while I am at speeds around 20 to 25mph or about 3000 RMP's. At any other speed or throttle position the engine runs great. One thing that is noticable is when the backfiring occurs the Tachometer starts running up to 5500 RMS and back down to 2000RMPs.
While the Tach is doing this the engine is not reving higher or lower just backfiring slightly. Makes me think it may be a coil problem. One thing that makes it go away for a bit is to take it out of that speed range, Giving it more gas or slowing down.

Need a starting point on troubleshooting. Called the dealer and they want 350 dollars to hook it up on the computer.

1997 SeaRay, 190, bowrider

5.7L EFI with alph one out drive.

Engine hours at 250 hours.

I have had the boat for a couple of months now, using every weekend, filled up the gas tank 8 times already so I know it isnt bad gas. Problem isnt getting worse or going away.

Have ordered the manual and should be delivered tomorrow but I dont think that is really going to help with troubleshooting this problem.

Thanks for the help in advance.
Derrick

 

[xltier]

Re: 1997 SEARAY Backfiring

try unhooking the coil tach wire to see if the tach has a short.the one i had wouldnt even start.

 

[JustJason]

Re: 1997 SEARAY Backfiring

uhmmm.....
First... 350 is a bit much to "hook it up to the computer".
I think either you are embelishing.... or your dealer is an absolute theif.
2nd.... your going to be hard pressed to diagnose this without a scan tool.
You can do it the old fasion way with a DMM and the books. But you'd need both the DMM and the books and a clear understanding of both.
My advice.... find another dealer.... or stop embelishing.

 

[derrick.w.wagner]

Re: 1997 SEARAY Backfiring

I wish. the dealer wants 320 plus tax. He said the money will goto fixing the problem after he finds out what it is.

 

[Uraijit]

Re: 1997 SEARAY Backfiring

That doesn't seem too fair, if it proves to be a $25 coil...

Just out of curiosity, what sort of computer connector does it have? You might be able to plug into it with a laptop and a very simple cable, and get a data stream out of it...

I'll even make you the cable, if you want to give it a shot.