Oil fouled spark plugs Suzuki DF90

[rrspin]

I have a 2007 Suzuki DF90 4 stroke EFI with low hours. Last couple times out I noticed a loss of power when travelling at higher than trolling speed. Motor would run a few seconds at the appropriate speed and then back down for a few seconds and then pick back up. And so on, and so on. Water pump is working fine.

Since my last trip I have changed the spark plugs and to my surprise 2 of the 4 had oil fouling (cylinder 3 & 4). Never previously had oil fouled plugs.

Before I go back out I was hoping to get some advice on possible causes of the intermittent power issue. My ideas include:

1: Spark plugs were ready for replacement and the old ones were preventing me from getting full power
2. The battery may not have had a good charge (not sure why that would impact motor performance once started but that's why I'm asking)
3. The thermostat is acting up and may need replacing
4. There is a microscopic amount of what appears to be oily fuel leaking from the fuel pump

Thanks for your thoughts...

 

[charleso]

If your battery is getting weak, it will cause the fuel pressure to drop. EFI will not run just off of alternator output. It is intended to keep a properly charged and functioning battery at optimum output for the battery to provide power to the electrical system. Get your battery load tested, replace it if it is weak. The environment a battery operates in on a boat can be very hard on a less than ideal battery.