Hi All!
Hoping to get some feedback on next steps for troubleshooting our 1997 Searay 175 - Mercruiser 3.0 LX with EST.
Our issue started a couple years ago, and I have suspicions we moved on to a separate issue during the process.
- 2 years ago, boat ran great, then all of a sudden on the water, it would be hard to start/and idle but once we got going it had full power and ran fine up on plane. Suspected a fuel issue, and most likely the carb.
- I rebuilt the carb that summer and tried my best to clear all the passages out. Boat still had the same symptoms. Checked the anti-syphon, fuel filters, changed the fuel, and in the end changed the mechanical fuel pump. Issue still existed.
- Checked the compression on all cylinders, looked normal (I think around 135 per cylinder)
-Last summer, all signs still pointed to a carb issue. So we purchased a new carb (from National Carbs) and installed it. It appeared to run smoother, we took it out on the water and I was happy with it at this point. Next time out, I was not with the boat myself, but now the boat had black smoke out the exhaust, you could smell it. Boat was now running really rough. Symptoms look to be running really rich, I verified the Choke was operating normally and was open after warm-up.
Yesterday I checked all of the following.
- Vacuum system - 19 in/hg and shows pretty steady at idle. Vacuum test.MOV
- Timing - verified the base timing to be 1 degree BTDC, but after jumpers removed it went up to 14-15 degrees BTDC ? Timing.MOV
- Continuity checked all the Ignition components in the service manual and they were all good.
- Verified the mechanical fuel pump we changed is outputting only 4.5PSI (was hoping it was high causing the issues).
- Next step is to re-check the compression on all cylinders again
- Is there a easy way to check that spark is getting to all cylinders?
Could the new Carb be the culprit again? something stuck? Boat starts easily, but we need to have the idle adjusted to 1100 rpm to run somewhat smooth and doesn't sound super happy when you try to increase the RPM's, engine shakes a significant amount from normal.
See videos above for a couple examples.
Thank you all for your time!
Andrew
Hoping to get some feedback on next steps for troubleshooting our 1997 Searay 175 - Mercruiser 3.0 LX with EST.
Our issue started a couple years ago, and I have suspicions we moved on to a separate issue during the process.
- 2 years ago, boat ran great, then all of a sudden on the water, it would be hard to start/and idle but once we got going it had full power and ran fine up on plane. Suspected a fuel issue, and most likely the carb.
- I rebuilt the carb that summer and tried my best to clear all the passages out. Boat still had the same symptoms. Checked the anti-syphon, fuel filters, changed the fuel, and in the end changed the mechanical fuel pump. Issue still existed.
- Checked the compression on all cylinders, looked normal (I think around 135 per cylinder)
-Last summer, all signs still pointed to a carb issue. So we purchased a new carb (from National Carbs) and installed it. It appeared to run smoother, we took it out on the water and I was happy with it at this point. Next time out, I was not with the boat myself, but now the boat had black smoke out the exhaust, you could smell it. Boat was now running really rough. Symptoms look to be running really rich, I verified the Choke was operating normally and was open after warm-up.
Yesterday I checked all of the following.
- Vacuum system - 19 in/hg and shows pretty steady at idle. Vacuum test.MOV
- Timing - verified the base timing to be 1 degree BTDC, but after jumpers removed it went up to 14-15 degrees BTDC ? Timing.MOV
- Continuity checked all the Ignition components in the service manual and they were all good.
- Verified the mechanical fuel pump we changed is outputting only 4.5PSI (was hoping it was high causing the issues).
- Next step is to re-check the compression on all cylinders again
- Is there a easy way to check that spark is getting to all cylinders?
Could the new Carb be the culprit again? something stuck? Boat starts easily, but we need to have the idle adjusted to 1100 rpm to run somewhat smooth and doesn't sound super happy when you try to increase the RPM's, engine shakes a significant amount from normal.
See videos above for a couple examples.
Thank you all for your time!
Andrew
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