Mercruiser 3.0L Misses while trimming under power...

[jcohen58]

The motor 3.0L ( 115 hp?) runs like a top... but sometimes ( seems like early morning or coming back in the late ( moist ) dark many times.. but not always..??) I get the " burp" or missing.. almost stalling feeling.. if I hit the trim and/or hold it a second...

Definitely feels like an electrical short or power drain problem.. anyone had/fixed this problem??

I just want to know where to start so I don't rip into it with very limited work time... It's also tough to spot cause it's intermittant...

Thanks in advance for your help...

 

[bamadave]

Re: Mercruiser 3.0L Misses while trimming under power...

Welcome aboard! check out Don's reply on vinnies thread about the same problem.

 

[searay3]

Re: Mercruiser 3.0L Misses while trimming under power...

Make sure the pins/pivots of the drive are properly lubed. Check the connections on the batteries and the pump and solenoids. The pump does draw amperage. Could be a battery and or charging issue. Check the condition/age of the batteries as well as alt output. Could be the voltage is dropping enough to make the ignition stutter. If it all looks good, may be the pump itself, in which case you would have to measure the amp draw.

 

[drvred]

Re: Mercruiser 3.0L Misses while trimming under power...

Had the same problem with my 140.
I cleaned the main plug on the back of the motor with electrical contact cleaner and fixed it.

 

[jcohen58]

Re: Mercruiser 3.0L Misses while trimming under power...

Make sure the pins/pivots of the drive are properly lubed. Check the connections on the batteries and the pump and solenoids. The pump does draw amperage. Could be a battery and or charging issue. Check the condition/age of the batteries as well as alt output. Could be the voltage is dropping enough to make the ignition stutter. If it all looks good, may be the pump itself, in which case you would have to measure the amp draw.

Thanks boys...

Sounds like I have a bunch of connection cleaning, checking, and tightening to do..hopefully before I get out this weekend...Should I check the Alternator output at higher revs?? The pins/pivots idea is vexing Searay.. what are those you refer to??

Thanks again for the input all...saves lots of aimless wandering and headscratching...

Jeff

 

[Pst76]

Re: Mercruiser 3.0L Misses while trimming under power...

Just was able to catch your question on the other thread, These guys hit it right on. My charging issue was due to bad connections on the cables. The original thing that compounded the low voltage was started due to my bilge pump switch getting stuck on and did not know it. I have a heavy duty pump in the boat and it drew more power than what the stator could keep up with. Pump had been on for about 45 min and I did not realize it. My battery had drawn down and had just enough to keep the boat running but as soon as I hit the trim it pulled volts down enough to miss fire motor.

 

[jka]

Re: Mercruiser 3.0L Misses while trimming under power...

I had the same issue with my omc 5.0 efi on a 95 four winns 190 horizon. I had the alternator replaced and it didn't solve the issue. I had the trim motor disassembled and it was fine. ( brushes were cleaned ). Finally, the mechanic changed the plugs which were nearly original. It solved the issue.
I was getting a big hiccup, stutter, stumble, what ever you want to call it when the trim was touched under power. the mechanic said the plugs, being older, were drawing too much...causing the stutter.
Change your plugs.