Expericing High RPM sputter not Low RPMs!

[Galaxytandy]

Hello again Boaters!
I have a OMC 350 engine that seems to sputter at High RPMs only after running the engine for about 40'mins or so! At low RPMs it doesn't sputter at all! Also I've experience a jolt on the motor when trimming the outdrive up and down! The RPM sputter is irritating me! I use to work on SBCs back in the day and it feels like a cap and rotor issue plugs wires etc..

 

[alldodge]

Your saying sputtering, would you say its coughing or close to backfire? If it is then it may be running low on fuel

 

[Galaxytandy]

Deleted message

 

[alldodge]

It's sputtering like somethis is loose! I don't think it's fuel related because it would not run at all al the time right l? Also I he drop out n voltage when I hit my trim red flags maybe I don't have enoug volts?

Sorry I'm old but I didn't understand what you just said.

 

[Galaxytandy]

Sorry Aldodge
What I was saying it's sputtering at high rpms like it's not gettting spark! Almost like a back fire sound! I didn't think it was the fuel pump because if it was it sputter at all times correct? The voltage dropping when I trim my outdrive seems like it could be a battery issue! So I'm not sure if the battery could be the problem? Sorry for not being clear!

 

[Galaxytandy]

Alldodge
I'm beginning to think I have a ALT issue. I just came home to start the boat and with the KEY on the Volts gauge doesn't even move. I started the boat and the gauge moves up slightly, ID say around 8 volts running. When I rev the motor it will not go past 10 bolts! any thoughts?
Chris

 

[alldodge]

Many times when a motor misses at high rpm its caused by lack of fuel, but with the voltage being that low, it would also show similar issues. I would start with putting a meter on the battery and then ALT post. If it shows similar readings then the ALT needs repair/replace

 

[Galaxytandy]

Will do thank you I will try those items this week and get back to you!

 

[Galaxytandy]

ALLdodge!
UPDATE: I placed a multi meter on my battery to test my alternator. While engine running the meter was reading 14 volts which tells me the ALT is charging the battery. So It may be fuel related. What are should I check first related to fuel?
Chris

 

[Bondo]

What are should I check first related to fuel?

Ayuh,.... The fuel Filter(s),...