240 EFI stalling problem

[fender1983@gmail.com]

Spent whole day on the lake. Tried to restart engine, it would idle for short period of time and stall. Had to restart it 6-10 times before i was able to shift to forward and give it throttle. Once i got it running it would pull without any issues, no power losses.

Then we went to a restaurant and an hour later same issue. I wanted to warm up the engine while tied to the dock but it kept stalling.

Boat got new water separating fuel filter before last winter (part of winterization process). Automotive gas, i do not suspect any water in fuel. Fuel have been stabilized and pretty fresh.

Any ideas where to look? Is it common problem with these?

 

[fender1983@gmail.com]

Ordered 13536A14 port temp sensor because it seems to be common cause based on google search results. I am "grounded" to a smaller inland lake instead of great lakes for this weekend...and buying a paddle too. Worst case scenario we would use a man power to get to dock.

My buddy suggested unplugging temp sensor wires and default it to coldest setting until engine warms up and then plug it back. ( i may try it too if it doesn't start)

 

[Dr Honda]

First.... when on the great lakes... you are required to have all "Open water" equipment. (Paddle, radio, flare gun)

Second... unplugging the port side sensor doesn't default it to anything. The ECU may go into limp mode. The Gen1 240EFI engine has some stupid things... one is... the port side temp sender, and the TPS are actually tied together, and give a fuel trim to the ECU. SO... if it doesn't go into limp mode... it will go to "Max" fuel trim, and it may make it a real pain to get restarted.

When you start it at the dock... what is the RPM? Also... you said that there wasn't a loss in power after... so what was your peak RPM?

 

[fender1983@gmail.com]

RPM is about 1000-1100 when it starts and idles properly. When it starts struggling it goes down to 600 or so. I don't know what my max rpm was, we cruised at 4200 rpm 30 mph. (but i get the idea, if rpm don't go high enough it would indicate bad TPS sensor).

As far as unplugging goes, i will experiment on the driveway on the hose, but it's not realistic because pump won't have any water to load the engine on idle.

Limp mode may be okay to get it started and warmed up, but like you said, if i flood it with gas, game over (got tow insurance as a last resort).

New sensor is coming between Friday and Monday. We will go to inland lake tomorrow and bring paddles


P.S. Got my boat checked by Coast Guard coast guard auxiliary and passed. Paddle is an optional equipment and won't do me any good when boat launch is miles away (we are on lake St Clair btw). I am going to buy anyway, because it will be enough on inland lake.

 

[Dr Honda]

I was looking for peak RPM as an indication of one or more dropped spark plugs.

Normally the sensors don't go intermitant... and if one failed... it would go VERY rich. (and stay that way)

After it gets over the poor idle, and clears out... will it idle OK after?

 

[fender1983@gmail.com]

Once it warmed up it idles perfect. I can restart after without any issues. Almost like carburetor

 

[fender1983@gmail.com]

Can't tell what max rpm i get, because it gets to 4k rpm and drops to zero on the tach. The engine keeps revving up, so it's a tach/electrical issue. Damn thing is full of issues

 

[Dr Honda]

Well... I would start with looking at the electrical connections at the engine. Hopefully you can just find a little corrosion, and get the tach working. If not, you should get an other way of checking the RPM.

 

[fender1983@gmail.com]

Tried unplugging sensor and it started right up in my garage. I think it’s bad sensor that’s causing cold start issues