jakwi
Petty Officer 2nd Class
- Joined
- Jan 7, 2019
- Messages
- 184
Hi all, I'm hoping that someone can point me in the right direction.
I have a mercruiser repower 357 alpha 4v. Which is just a standard carbed 350 with the thunderbolt iv ignition.
Before today it had been running great. On the way back to the ramp today I was cruising along on plane at about 3500 rpm. All of a sudden it died out of no where. I restarted a couple of time and it would idle fine but as soon as I gave it any power it would cut out.
I opened the engine cover and the bilge was pretty full of water, maybe up to the bottom of the oil pan and spraying out of the starboard side exhaust manifold feed hose. Apparently the hose clamp broke. I stole a clamp from somewhere else and fixed that issue. The bilge pump did its job and I thought we would be back in business.
However I found that if I ran anything over 1200rpm it would eventually cut out. 1400 rpm it took maybe 7 or 8 min. 3000 rpm maybe a min. 4800 rpm 10 or 15 seconds.
I tried opening the gas cap, possible vent issue, no go, pulled the spark arrestor in case it was plugged no go, chegood bat voltage, 13.9, 14.5 at 1400 rpm. No issue there.
So we idled back to the ramp, which sucked, but ok.
Back at the house I checked for fuel. Ran it til it cut out and then after it died "revved" the throttle, plenty of gas visible in the carb, so fuel isn't the issue.
Pulled the distributor cleaned the contacts. All good there.
New plugs, properly gapped were installed about a month ago. No more than 10 running hours ago.
I followed the troubleshooting guide achris, posted a while back.
Everything looks good, because the issue always happens at high rpm. It always restarts and idles perfectly.
So in my mind I'm down to cool or ignition sensor. The coil is a Sierra pn I replaced last year. Or possibly the module, I hope not.
Is there anyway to know whether it's the coil or the sensor? Which is the most likely failure? I hate to throw parts at it if I'm not sure.
Bear in mind the only issue was a lot of spraying water on the starboard side near the spark plugs. Before that it was running great. The coil, distributor, etc never got wet at all.
thanks for the input guys!
I have a mercruiser repower 357 alpha 4v. Which is just a standard carbed 350 with the thunderbolt iv ignition.
Before today it had been running great. On the way back to the ramp today I was cruising along on plane at about 3500 rpm. All of a sudden it died out of no where. I restarted a couple of time and it would idle fine but as soon as I gave it any power it would cut out.
I opened the engine cover and the bilge was pretty full of water, maybe up to the bottom of the oil pan and spraying out of the starboard side exhaust manifold feed hose. Apparently the hose clamp broke. I stole a clamp from somewhere else and fixed that issue. The bilge pump did its job and I thought we would be back in business.
However I found that if I ran anything over 1200rpm it would eventually cut out. 1400 rpm it took maybe 7 or 8 min. 3000 rpm maybe a min. 4800 rpm 10 or 15 seconds.
I tried opening the gas cap, possible vent issue, no go, pulled the spark arrestor in case it was plugged no go, chegood bat voltage, 13.9, 14.5 at 1400 rpm. No issue there.
So we idled back to the ramp, which sucked, but ok.
Back at the house I checked for fuel. Ran it til it cut out and then after it died "revved" the throttle, plenty of gas visible in the carb, so fuel isn't the issue.
Pulled the distributor cleaned the contacts. All good there.
New plugs, properly gapped were installed about a month ago. No more than 10 running hours ago.
I followed the troubleshooting guide achris, posted a while back.
Everything looks good, because the issue always happens at high rpm. It always restarts and idles perfectly.
So in my mind I'm down to cool or ignition sensor. The coil is a Sierra pn I replaced last year. Or possibly the module, I hope not.
Is there anyway to know whether it's the coil or the sensor? Which is the most likely failure? I hate to throw parts at it if I'm not sure.
Bear in mind the only issue was a lot of spraying water on the starboard side near the spark plugs. Before that it was running great. The coil, distributor, etc never got wet at all.
thanks for the input guys!