"Engine stalled at 3200 RPM af
"Engine stalled at 3200 RPM after a 3-4 minute cruise. After it stalled, I could hear the water boiling in the intake manifold. The gauge was not above 140 deg. I checked the carb accellerator pump for fuel and it spit fuel like a King Cobra spitting venom. I had 12v on both sides of the coil but was afraid to check for spark due to the strong fuel odor.
I had just replaced the fuel pump, filters, cleaned the fuel lines, new fuel tank and fill/vent lines, also new dist. cap, rotor & plugs (.035 gap per engine ID tag).
The next morning I checked for spark and had plenty that stretched to one inch as I pulled the coil wire farther away from the block. The optic sensor in the dist. was rusty so I replaced it along with new plug wires because they were stiff and original 1987.
The beast fired right up with a set of ear muffs and ran fine for an hour with very good throttle reponse--never stalled or overheated--I know the garden hose kept it cool. It idles at 600 - 650 rpm. I took it to the lake at night and it started quickly and ran fine (nights are limited to 10 mph) but it did stall once after a 10 min. run when I pulled back quickly on the throttle; it seemed like it was not getting enough fuel since it sputtered as it died. It took a few minutes of cranking and throttle pumping then cranking it wide open throttle to restart; then it sputter started and ran fine.
The spark arrester is clean, the carb was rebuilt 2 yrs ago, fuel was fresh, the carb throat is crystal clean, but there is a crack in the side support of the spark arrestor stud bracket at the top of the carb.
It appeared to be interfereing with the butterfly when wide open so I gently separated them so not to bind. I cleaned and rebuilt the shift control with a new trim harness and neutral safety switch before this happened along with replacing the gauge wire harness from the engine due to the poor wire condition. Never disconnected the cables at the engine but installed new battery cables with tight grounds.
After reading several similar posts I think the problem may be a hot (felt hot and water was boiling in it) intake manifold vapor lock problem perhaps from scale build up. It has a new fuel pump and 2 yr old thermostat--engine gauges are new Faria and it is not running hot at cruise speed but does get hot (200 deg.) at idle and then drops to 140 deg. under way. It has had the lower unit waer pump and bellows and inlet hose replaced two years ago.
This year I have done a complete refurb after gutting the boat down to the hull due to finding the wood was wet mulch and the foam was water logged. All wood was replaced with CPES treated wood and 5 gallons of epoxy and glass cloth.
The starboard exhaust manifold is 2 yrs old while the port one is original and was welded after the block froze in 1996. Last fall while draining the block alot of chunky rust particles and sediment came out of the drain holes after I probed them a few times.
What is your expert advice?"
"Engine stalled at 3200 RPM after a 3-4 minute cruise. After it stalled, I could hear the water boiling in the intake manifold. The gauge was not above 140 deg. I checked the carb accellerator pump for fuel and it spit fuel like a King Cobra spitting venom. I had 12v on both sides of the coil but was afraid to check for spark due to the strong fuel odor.
I had just replaced the fuel pump, filters, cleaned the fuel lines, new fuel tank and fill/vent lines, also new dist. cap, rotor & plugs (.035 gap per engine ID tag).
The next morning I checked for spark and had plenty that stretched to one inch as I pulled the coil wire farther away from the block. The optic sensor in the dist. was rusty so I replaced it along with new plug wires because they were stiff and original 1987.
The beast fired right up with a set of ear muffs and ran fine for an hour with very good throttle reponse--never stalled or overheated--I know the garden hose kept it cool. It idles at 600 - 650 rpm. I took it to the lake at night and it started quickly and ran fine (nights are limited to 10 mph) but it did stall once after a 10 min. run when I pulled back quickly on the throttle; it seemed like it was not getting enough fuel since it sputtered as it died. It took a few minutes of cranking and throttle pumping then cranking it wide open throttle to restart; then it sputter started and ran fine.
The spark arrester is clean, the carb was rebuilt 2 yrs ago, fuel was fresh, the carb throat is crystal clean, but there is a crack in the side support of the spark arrestor stud bracket at the top of the carb.
It appeared to be interfereing with the butterfly when wide open so I gently separated them so not to bind. I cleaned and rebuilt the shift control with a new trim harness and neutral safety switch before this happened along with replacing the gauge wire harness from the engine due to the poor wire condition. Never disconnected the cables at the engine but installed new battery cables with tight grounds.
After reading several similar posts I think the problem may be a hot (felt hot and water was boiling in it) intake manifold vapor lock problem perhaps from scale build up. It has a new fuel pump and 2 yr old thermostat--engine gauges are new Faria and it is not running hot at cruise speed but does get hot (200 deg.) at idle and then drops to 140 deg. under way. It has had the lower unit waer pump and bellows and inlet hose replaced two years ago.
This year I have done a complete refurb after gutting the boat down to the hull due to finding the wood was wet mulch and the foam was water logged. All wood was replaced with CPES treated wood and 5 gallons of epoxy and glass cloth.
The starboard exhaust manifold is 2 yrs old while the port one is original and was welded after the block froze in 1996. Last fall while draining the block alot of chunky rust particles and sediment came out of the drain holes after I probed them a few times.
What is your expert advice?"