ENGINE: 1990 Johnson 60HP VRO (model no: J60ELESM)
ANY suggestions beyond what has already been checked/ruled out as a the problem with this motor would be greatly appreciated. A preliminary "thank you" to anyone/everyone who takes the time to reply or suggest further troubleshooting:
Its a 1990 Johnson 60 HP VRO model. The power head was rebuilt two years ago. Compression is good (110, 115, 110) and has a brand new power pack (spark is good).
THE PROBLEM: I had the motor installed on my 1984 17' Grady White at the beginning of last summer. It ran well the firt 5/6 trips. It then started to develop the "problem" - after running 3/4 Throttle it woud suddenly bog down and operate only at very low RPMs (just barely pushing the boat). After sitting for a 1/2 hour or so, it would run fine again at low throttle up to WOT. The last 6 trips or so of last summer it would 'bog down' more frequently and quicker. I winterized the engine this past winter. Gas was treated. This spring the set up got a new RACOR filter, new plugs, the tattletale hose was relocated to run over the top of the engine block (service bulletin that I found for this make/model with issues of air pockets in the water jacket), new t-stat installed. The motor ran off the '84 Grady White belly tank last summer and for the first 4 time this summer. When I changed the RACOR filter, there were reddish/brown flecks throughout the filter. The motor ran okay the first 2 or 3 times this past summer, but would again bog down at higher RPMs. I took it to a reputable Johnson/Evinude dealer on the south shore (MA) and they installed a new power pack. That did NOTHING - same problem with bogging down, same frequency. (the receipt said "no output from power pack" - this could not have been true as I had run the motor 2 days before [separate issue - but it has a new power pack nonetheless])
Worried about the belly tank being varnished, I put the motor on a deck tank, fresh gas put in 3 new "Q" plugs. Same bogging down problem, now occurring at low RPMs (the motor will not power up at all). I changed the in-line fuel filter (the little white plastic one in the cowling) and took it out this past weekend. The motor NEVER powered up, and was bogged down from the moment it was in the water.
SYMPTOMS: The past few times upon starting there is a lot of smoke that comes out of the engine. The deck tank is brand new along with the fuel line/fuel pump ball. The fuel line pump ball NEVER GETS HARD while the engine is running. In fact, pumping the fuel ball does not seem to anything at all - it doesn't affect the motor and it never pumps up hard. When I changed the plugs 2 weeks ago they looked oily and wet. The VRO is intact. When I pump the fuel ball, I have not noticed any leaking, and have not noticed any gas in the water around the motor. The motor does not stall (at times when going into gear it will), but will generally stays running, but acts as if it is either getting too much fuel and choking down or not enough fuel, starvation.
I am not sure if the marina that I bought the engine from 2 years ago rebuilt the carbs - I have not pulled them apart. I have read on this forum that if the powerhead was rebuilt, then it has to have a new fuel/VRO pump (the pump in this engine (VRO) pumps both the fuel and the oil). There does not appear to be any difference in the performance (or lack of performance) since taking the boat off the belly tank, though I am pretty sure the belly tank is probably varnished. VRO oil level is well above half full.
ANYONE out there have any educated thoughts on this? Its been two summers of disappointment with this motor and trying to troubleshoot. Thanks in advance!