Outboard stalls for no reason, then won't restart until engine cools

[joconnor]

Looking for some help!!!! We've been having an ongoing issue for actually years now. We have Suzuki twin 175 outboards that were purchased and installed in 2013. In 2013 or 2014, we were going mid speeds and struck a buoy and rope. Both engines shut down and would not restart despite the fact that there was only slight damage to a protective piece on the lower unit and not to the prop, lower unit, any other moving parts, etc. We had to get towed in and we took the boat to a repair shop. We were told the engine cylinders were clogged and needed cleaned out. The explanation was the clogging was due to us having the engine at idle "too much." Oddly enough, the engines were still very new at this time.

Fast forwarding - since then we have had numerous incidents where we have struck an object (stick, sand bar) causing one or both engines to stall. HERE'S THE ISSUE: Once the engine(s) stall, we cannot restart them for an unpredictable amount time. I struck a sandbar at just above idle speeds and the starboard engine quit. After waiting about 1-2 hours (and several attempts to restart) it finally restarted. In other cases, the boat has been towed in, or limped home on one engine. The very next time we use it, it starts no problem. All the mechanics we have taken it to have no explanation for us because the boat is not experiencing the problem at the time when we are at repair shop.

I wonder if there is some sensor somewhere that is tripped when a stall occurs and is then reliant on the engine to cool to a certain point?

Any ideas are appreciated, we just don't know where to go from here !!!!

[aquamort]

DF175's im guessing? Does this problem happen to both? What exactly was damaged initially and was it the same damage to both engines? Did rope around the props cause the engine to stall? There's a lot of if's i think at the moment?

I'd start with a thorough going over of all connections, maybe a big sudden jolt has dislodged something?

[redlowrey]

Looking for some help!!!! We've been having an ongoing issue for actually years now. We have Suzuki twin 175 outboards that were purchased and installed in 2013. In 2013 or 2014, we were going mid speeds and struck a buoy and rope. Both engines shut down and would not restart despite the fact that there was only slight damage to a protective piece on the lower unit and not to the prop, lower unit, any other moving parts, etc. We had to get towed in and we took the boat to a repair shop. We were told the engine cylinders were clogged and needed cleaned out. The explanation was the clogging was due to us having the engine at idle "too much." Oddly enough, the engines were still very new at this time.

Fast forwarding - since then we have had numerous incidents where we have struck an object (stick, sand bar) causing one or both engines to stall. HERE'S THE ISSUE: Once the engine(s) stall, we cannot restart them for an unpredictable amount time. I struck a sandbar at just above idle speeds and the starboard engine quit. After waiting about 1-2 hours (and several attempts to restart) it finally restarted. In other cases, the boat has been towed in, or limped home on one engine. The very next time we use it, it starts no problem. All the mechanics we have taken it to have no explanation for us because the boat is not experiencing the problem at the time when we are at repair shop.

I wonder if there is some sensor somewhere that is tripped when a stall occurs and is then reliant on the engine to cool to a certain point?

Any ideas are appreciated, we just don't know where to go from here !!!!

'''''''''''''So I am assuming when cold, both engines start and run fine, Then when they are hot they both stop. Do both the engines crank over and not start, or you turn the key to the start position and nothing happens. This does not sound like a problem that would be hard to fix.

[joconnor]

Yes I believe they are DF175. yes rope interfered causing the stall. The engines both start fine when cold. If an external object causes one or both engines to stall, when the key is turned to restart, an alarm goes off, the engine(s) don't crank but the rpm guage goes up to 1200 or so rpm for a couple seconds then back to zero. Then if we wait long enough the engine will restart. As to how long we have to wait is unpredictable. Sometimes a couple hours or sometimes the next boating trip. It's almost as if something is tripped in the system when an object is hit then causing the system to prevent the engine from restarting until the engine temperature has reached a certain point??

[artdf175]

It is normal for the rpm guage to advance and then drop to zero when the key it initially turned to the on position
You didn't address the question Red ask about the engine turning over when you are faced with this situation-- you just say it won't start

[aquamort]

Yep that's normal as Art said when you turn key on. If there is no cranking as you say I'd be looking at neutral switch/gear linkages. May not have anything to do with heat and is my guess it doesn't.

[joconnor]

The engine(s) do not turn over when the key is turned. We'll have to revisit the linkage possibility. Thanks everyone so far for your input, much appreciated!!

[Solarman]

Any chance the control levers for both engines were jammed at the time to hit the object(s)? If possible, you may have slightly changed the position of the neutral switch in the controls. Though i don't think it has to cool down, as much as wiggling the throttles just right for the switch to activate.

Just a thought. Good luck. Post back when able.