I'm having some strange problems this summer.
Motor - Mercury 175 Blackmax, oil injected, carbureted.
When I first put the boat in the water this spring it did not have enough power to get up on plane. I didn't have enough time to work on it or try anything. A week later I put the boat in the water to troubleshoot and it was still running rough, I messed with taking one plug wire off at a time to see if one was causing a problem. I couldn't tell a difference at idle speed so I put them all back on and was going to do one plug at a time at higher power so that it would be more noticeable, however when I put all the plugs back on, the motor took off and ran normal, I figured it must have been too much fogging oil last fall causing the problem and it just needed time to burn off. I ran the motor for about an hour.
The next time I put the boat in the water it had the same symptoms of running really rough and didn't have enough power to get on plane. I ran it for a few minutes and then all of a sudden it started firing normal and the boat took off and ran normal, used the boat on and off for the rest of the day (with an hour or two to cool off in-between runs) and the motor worked great each time.
Now when starting the motor using fast idle it seems to start normal. When I put it into regular idle it dies. If I can put it into gear fast enough it will stay running but does not have full power, the RPM's max out at around 2500 and the boat will not get on plane. When the motor is in fast idle the RPM's will go up to 5500 (normal rpms) but only to 2500 when throttle all the way down.
Here's what I have tried.
New plugs (much improved the fast idle smoothness of the motor, but didn't fix the problem)
water remover in gas tank
seafoam in gas tank (I may not have given the seafoam enough of a chance to work. I ran it on fast idle for about 10 minutes)
Any suggestions or ideas are greatly appreciated!
I've done lots of searching for idle problems etc, but not finding anything with the same symptoms.
Thanks Everyone
Jason
Motor - Mercury 175 Blackmax, oil injected, carbureted.
When I first put the boat in the water this spring it did not have enough power to get up on plane. I didn't have enough time to work on it or try anything. A week later I put the boat in the water to troubleshoot and it was still running rough, I messed with taking one plug wire off at a time to see if one was causing a problem. I couldn't tell a difference at idle speed so I put them all back on and was going to do one plug at a time at higher power so that it would be more noticeable, however when I put all the plugs back on, the motor took off and ran normal, I figured it must have been too much fogging oil last fall causing the problem and it just needed time to burn off. I ran the motor for about an hour.
The next time I put the boat in the water it had the same symptoms of running really rough and didn't have enough power to get on plane. I ran it for a few minutes and then all of a sudden it started firing normal and the boat took off and ran normal, used the boat on and off for the rest of the day (with an hour or two to cool off in-between runs) and the motor worked great each time.
Now when starting the motor using fast idle it seems to start normal. When I put it into regular idle it dies. If I can put it into gear fast enough it will stay running but does not have full power, the RPM's max out at around 2500 and the boat will not get on plane. When the motor is in fast idle the RPM's will go up to 5500 (normal rpms) but only to 2500 when throttle all the way down.
Here's what I have tried.
New plugs (much improved the fast idle smoothness of the motor, but didn't fix the problem)
water remover in gas tank
seafoam in gas tank (I may not have given the seafoam enough of a chance to work. I ran it on fast idle for about 10 minutes)
Any suggestions or ideas are greatly appreciated!
I've done lots of searching for idle problems etc, but not finding anything with the same symptoms.
Thanks Everyone
Jason
Any good how-to's?