Woodnaut
Chief Petty Officer
- Joined
- Jul 4, 2007
- Messages
- 634
The patient is a 1987 Johnson 70 hp (3 cyl with VRO). Model appears to be J70ELCUR.
History & Symptoms: Friend bought rig used. Pulled off carbs and cleaned, replaced plugs and old gas/oil lines. Ran approximately 10+ hours with good performance. Cruising at 3/4 throttle when engine slowed down and then died. Engine restarted and ran smoothly at half throttle, but died when attempting to go to full throttle. Would not restart. Back at dock when cranking engine noticed small amount of fuel running out of bottom of air intake box on front of engine. Removed cover from air intake box and noticed the source of this fuel was short hose from very bottom of reed valve block (crankcase) to very bottom air intake box. Was eventually able to get engine started a few days later and ran OK at idle (using muffs).
Findings: Compression check on warm engine indicated 115 - 87 - 103 psi (top-cen-bot). Squeezed the heck out of the [gas] primer bulb - carbs filled up and then stopped taking fuel so I assume float, needles and seats are OK. Pulled the carbs, then pulled the reed plate block assembly. Using flashlight could see small amount of light shining through every reed valve - estimating just a few thousandths gap on most with a few showing possibly as much as .020 - .025, but never noticed engine spitting fuel from carbs when running. When removing VRO assembly, did not get the gush of oil I expected when the oil supply line was removed. In fact, almost seemed as if a little gas was present at this point. VRO oil tank definitedly had oil in it.
Next Step: Buy 3 carb rebuild kits and some new reed valves and go back together? Is a rebuilt kit available for the VRO or is this a sealed assembly that is not rebuildable? Compression readings are somewhat concerning. Pull the head first and take a look inside before spending money on anything? Gents - your comments are most welcome. Regards - Woodnaut
History & Symptoms: Friend bought rig used. Pulled off carbs and cleaned, replaced plugs and old gas/oil lines. Ran approximately 10+ hours with good performance. Cruising at 3/4 throttle when engine slowed down and then died. Engine restarted and ran smoothly at half throttle, but died when attempting to go to full throttle. Would not restart. Back at dock when cranking engine noticed small amount of fuel running out of bottom of air intake box on front of engine. Removed cover from air intake box and noticed the source of this fuel was short hose from very bottom of reed valve block (crankcase) to very bottom air intake box. Was eventually able to get engine started a few days later and ran OK at idle (using muffs).
Findings: Compression check on warm engine indicated 115 - 87 - 103 psi (top-cen-bot). Squeezed the heck out of the [gas] primer bulb - carbs filled up and then stopped taking fuel so I assume float, needles and seats are OK. Pulled the carbs, then pulled the reed plate block assembly. Using flashlight could see small amount of light shining through every reed valve - estimating just a few thousandths gap on most with a few showing possibly as much as .020 - .025, but never noticed engine spitting fuel from carbs when running. When removing VRO assembly, did not get the gush of oil I expected when the oil supply line was removed. In fact, almost seemed as if a little gas was present at this point. VRO oil tank definitedly had oil in it.
Next Step: Buy 3 carb rebuild kits and some new reed valves and go back together? Is a rebuilt kit available for the VRO or is this a sealed assembly that is not rebuildable? Compression readings are somewhat concerning. Pull the head first and take a look inside before spending money on anything? Gents - your comments are most welcome. Regards - Woodnaut
