Re: [omc-boats] Fw: diagnosis needed

Hi Thomas,

Sorry to hear about your frustrating engine. It's hard to speculate, but from what you've said you worked on with respect to your engine re-assembly and ignition tune-up, I'd guess the problem is fuel or carb related. Can you get a scope on the engine to make sure you have no primary or secondary ignition issues? That will at least verify the coil and HT wires are OK. My guess is there's fuel contaimination or issues with the carb that are causing the backfiring and lack 0f power issues beyond idle. You didn't say what the compression was in each cylinder before and after you adjusted the valves? What sort of vacuum reading is the engine pulling at idle? Hope these ideas help....

Lee Shuster
SLC, UT
  ----- Original Message -----
  From: Thomas Klauber
  To: omc-boats-digest@...
  Sent: Tuesday, August 10, 2004 2:20 PM
  Subject: [omc-boats] Fw: diagnosis needed

  ----- Original Message -----
  From: Thomas Klauber
  To: omc-boats@...
  Sent: Tuesday, August 10, 2004 3:13 PM
  Subject: diagnosis needed

  I put the 69 Rogue in the river today. Boy did she run bad. I can not figure out the diagnosis and need help. I recently did a tear down of the engine for water in the oil last year. It is a Chevy 307ci/210hp V8. Compression seemed OK. I was not able to find any cracks in the heads or block and reassembled the motor with new gaskets and back in she went. I assume it must have been water leaking around the intake manifold gasket. Anyway no water in the oil this year. I have been trying to get in the water this year but it seems to be one thing after the other. Today I put in and she would crank and idle no problem whatsoever but idling down below 800 rpm to put her in gear is iffy and she will stall when you put her in gear unless you give it a little gas and she will catch up but it makes maneuvering in close quarters difficult. Anyway, once underway she does fine up to about 1200 rpm but above that she sputters, backfires and if you dont back off throttle she will quit. You can crank her out of the water and she will run fine, she will idle and will rev up to wherever you want in or out of gear, but under power she turns to jelly. I replaced the distributer cap, points,condensor earlier this year and she tuned up nicely. I checked the fuel pump output. I adjusted the valves earlier with the engine running and went about a full turn on each one. I will check the plug wires again. I see some seepage around the throttle body gasket but I don't think that it is significant. I did a carb. inspection earlier this year and it seemed OK so I think all screws at the carb. are tight. I did not put in a new carb kit. There does not seem to be too much play in the distributor. The coil is original or at least 20yrs old. Is the problem gas or ignition? Could it be something in the sterndrive? Any help would be appreciated. Tom Klauber
Received on Wednesday, 11 August 2004