Perkins T6.354 help diagnosing a problem
For those of you that have the time to indulge me, your advise, time, and experience is greatly appreciated.
A month ago I bought a Mainship 34 mk1 with a Perkins T6.354 160 hp, there is a racor fuel filter before the lift pump.
Okay, so here is what happened: first trip, total of about 11 hours, everything runs fine. Next trip after about 45 minutes on the first day of cruising, rpm surges and engine loses power as if it had ran out of fuel, can’t get the engine to restart, get towed back to marina, bleed the fuel system, and the engine starts right up. What I discover is that if the engine is getting fuel from the same tank as the fuel polisher, it sucks in a lot of air. So, it was user error and I’m back underway.
Here is where the problem starts.
The second day of cruising after about 5 hours, there is about a 100 rpm surge. I snap to attention thinking it’s happening again but after 5 seconds it settles and resumes as normal. I stop shortly after that.
Third day the same thing happens as above but happens 3 or 4 times throughout the day.
Fourth day it starts happening anywhere from every 10 minutes to once an hour. Eventually I have to keep pulling the throttle back to maintain 2000. Then I pull it back to 1750 and it stays there without noticeable surging for the last 2 hours of the day. When I approach the harbor I bring the throttle to idle but the engine will only go down to 1500. I get it into the slip and have to leave for a few days. I get back and the engine starts right up, idles at 700 and has excessive exhaust. Oil pressure and temp were normal throughout all this.
Any thoughts about what is going on?
Thank you for your help.