MErc 4 stroke woes

[captadamr]

Happy 4th of July to you all.

I am having a major issue with my 2 merc 115hp 4 strokes. When we test ran the boat it ran great, cruiseing around 30. over the last few days its been losing RPMs. I thought the filters were dirty, so i changed them. After changing them I couldnt get over 4K, today tried again and I couldnt get over 2500rpms. The engines idle really rough, and both exibit the same problem. Is it possible that air got into the fuel rail or injectors and thats why it wont rev higher??

Another possible reason, extremely far fetched, i think someone poured something into my fuel tank and its clogging up the system. i put 30 gal in and only hand tightened the cover, came back the next day and there were unkown footprints and I had to struggle to get the tank cover off with a tank key
Help please

[mneptune]

Originally Posted by captadamr

Happy 4th of July to you all.

I am having a major issue with my 2 merc 115hp 4 strokes. When we test ran the boat it ran great, cruiseing around 30. over the last few days its been losing RPMs. I thought the filters were dirty, so i changed them. After changing them I couldnt get over 4K, today tried again and I couldnt get over 2500rpms. The engines idle really rough, and both exibit the same problem. Is it possible that air got into the fuel rail or injectors and thats why it wont rev higher??

Another possible reason, extremely far fetched, i think someone poured something into my fuel tank and its clogging up the system. i put 30 gal in and only hand tightened the cover, came back the next day and there were unkown footprints and I had to struggle to get the tank cover off with a tank key

Help please

If it is happening to both engines, sounds like something in your fuel.
Mysterious footprints? Filler cap over tightened? I would hate to think it but someone may have indeed messed with your chit mon!! I hope that is not the case.

Don't run it again until it is checked by a certified mechanic. If it's sabotage, running any more fuel throuigh them could be a real disaster. Keep us posted as to the outcome.

[captadamr]

In case anyone wanted to know what happened

Worked on the motor til 8:30, and after 3 test runs got it all sorted.
1. ECM was finished on port motor, but now the tach that wasnt working, works and its running. Has trouble running at idle, no combustuon on #4, but it fires after 1200rpm, im thinking bad coil or wires, as plug is fine and put in a new injector,
2. Stbd Motor, burnt #3 plug, Plugged in the test light, and it said Shift position sensor, found out someone didnt put a pin in, that allowed the asselbly to slip. 10 cent pin, caused all the headache
Took on final test run, and got 5000rpm with the Aluminium props.