Originally posted 6/16 - RPM's have gone from 27 - 2800 down to 1900 in neutral. So far, have changed fuel filter, checked/adjusted linkage and removed/cleaned exhaust elbow (was pretty bad), checked air filter. Have gotten up to 2,100 rpms, and now warning buzzer is "chirpping", but no warning lights. Any suggestions? Steve
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This sounds stupid but...
Does the engine actually SOUND like it's running slower? That much of a change should easily be discernable. Or is the tach just dropping? I remember reading on here about issues with the tach pick-up. Are you changing engine speed from the helm pedestal handle? Is there any difference by moving the linkage on the engine itself?
Does the engine actually SOUND like it's running slower? That much of a change should easily be discernable. Or is the tach just dropping? I remember reading on here about issues with the tach pick-up. Are you changing engine speed from the helm pedestal handle? Is there any difference by moving the linkage on the engine itself?
Just Some Thoughts
Steve, I have the same engine. Last year I replaced a Perko filter with a new Racor. Problems from day one similiar in some respects to the problem you describe. My issue was in the Racor itself. Here are some of the steps others on this forum suggested to me. You've probably already thought of some or all of these: Connections - check all connnections from tank to injectors. Maybe something came loose. Fuel pickup tube in tank - pull the screen out on the bottom of the tube. It gets clogged and prevents fuel from flowing. Also cut a 1/2" off the bottom of the tube to prevent the pick up of crap from the bottom of your tank. Clean your tank - siphon the fuel out and scrub it down. Mine was very dirty. I also built a simple fuel polisher using the old Perko and a diesel fuel pump purchased at an automotive store and throughly cleaned my fuel. Check fuel line from tank to primary and primary to engine - take it off and blow through it. Be sure there are no obstructions. Replace if needed. Check the lift pump - apparently the lift pump on the 3GMF is not super strong. Over time it will start to fail. I replaced mine for about $90(?). Add a vacuum guage - this was eventually how I located my problem. It pinpointed the problem was between the gauge and the tank. The big relief was it was not my engine. Check passages (in/out) of the primary filter - this is where my problem was. It was the last place I looked because the Racor was brand new. I had a blockage in the "IN" port. Once I dealt with that (a 3 second fix) I had no more problems. Good luck, Joe Mullee
Steve, I have the same engine. Last year I replaced a Perko filter with a new Racor. Problems from day one similiar in some respects to the problem you describe. My issue was in the Racor itself. Here are some of the steps others on this forum suggested to me. You've probably already thought of some or all of these: Connections - check all connnections from tank to injectors. Maybe something came loose. Fuel pickup tube in tank - pull the screen out on the bottom of the tube. It gets clogged and prevents fuel from flowing. Also cut a 1/2" off the bottom of the tube to prevent the pick up of crap from the bottom of your tank. Clean your tank - siphon the fuel out and scrub it down. Mine was very dirty. I also built a simple fuel polisher using the old Perko and a diesel fuel pump purchased at an automotive store and throughly cleaned my fuel. Check fuel line from tank to primary and primary to engine - take it off and blow through it. Be sure there are no obstructions. Replace if needed. Check the lift pump - apparently the lift pump on the 3GMF is not super strong. Over time it will start to fail. I replaced mine for about $90(?). Add a vacuum guage - this was eventually how I located my problem. It pinpointed the problem was between the gauge and the tank. The big relief was it was not my engine. Check passages (in/out) of the primary filter - this is where my problem was. It was the last place I looked because the Racor was brand new. I had a blockage in the "IN" port. Once I dealt with that (a 3 second fix) I had no more problems. Good luck, Joe Mullee
Steve...
Your exhaust loop off the back of the engine gets carboned up over time. Make sure that this isn't a part of your problem. Could be why the alarm sounded-- possibly the engine running too hot. Sudden RPM drops and then not being able to get the engine (a 3GM Yanmar) over 2,200 RPM under load two seasons ago were the reasons I built a fuel polisher and cleaned out the tank. Apparently the engine was being fuel starved by a clogging filter from crap in the fuel. After cleaning the tank and polishing the fuel, the engine runs fine and my 2 mic Racor hasn't shown any signs of clogging on the vacuum gage.
Your exhaust loop off the back of the engine gets carboned up over time. Make sure that this isn't a part of your problem. Could be why the alarm sounded-- possibly the engine running too hot. Sudden RPM drops and then not being able to get the engine (a 3GM Yanmar) over 2,200 RPM under load two seasons ago were the reasons I built a fuel polisher and cleaned out the tank. Apparently the engine was being fuel starved by a clogging filter from crap in the fuel. After cleaning the tank and polishing the fuel, the engine runs fine and my 2 mic Racor hasn't shown any signs of clogging on the vacuum gage.
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