Dies Suddenly while Cruising - Page 3 - Maxum Boat Owners Club

mmwjr · 07-08-2016, 01:11 PM

Ok the new unit has white/red and white/green wires just like the origional connections. The only addition is the black wire that connects to ground.

JoDo · 07-10-2016, 04:17 AM

I replaced the ignition sensor and all and also the fuel pump for good measure since I had one. It started great. I set it to about 3000rpm for a spell, no problems, then left it idle for about 20 min at the dock. It ran great. I was so optimistic. Left the dock to head about 2 miles to the launch and about 200 yards out it stalled. I went immediately back to the carb and worked the throttle by hand. No fuel squirted, just a trickle. Hmm....plugged filter or needle? I could start it and after several attempts of putting in gear I could get going for a bit then it would stall. Then I noticed an interesting thing since I was running without the plastic cowl over the spark arrestor (the spark arrestor was left in place though)....water on the carb and pooling around the accelerator pump. Water was coming in tiny bits from the arrestor. Then when I looked into the carb I saw water beads on the upper butterfly plates. I still have major water in the fuel tank! How? I drained it before I first took it out. If I had a breach in the tank, wouldn't I have fuel in the bilge? After no less than 15 start/stall/sit episodes I finally made it to the launch. At least I have it home now and can work on it more easily.

JoDo · 07-10-2016, 04:44 AM

Here is the location of my fuel tank vent. Air goes in to equalize pressure correct? Does that mean water could get sucked in?

mmwjr · 07-10-2016, 05:17 AM

The vent is high enough that water should not get into it. If I recall you have owned this boat for years without this issue and the vent has always been in this location.

The upper plates are the choke, when you check they should have been opened all the way as the engine was at operating temp. If not the engine cannot breath and will choke off and stall. Do they move freely? Is the choke getting power?

JoDo · 07-10-2016, 05:51 AM

The choke plates over the front barrels (primary, correct?) were wide open The larger plate over the secondaries was still shut. I saw the beadlets of water on there and scattered about the top of the carb. I have had this boat a while and this has been an intermittent problem for a few years. Only this year it has become more frequent and consistent

mmwjr · 07-10-2016, 06:06 AM

Correct on the primary being the choke plates.

I forgot have you removed the fuel filter and poured the contents into a glass jar to look for water?

speedysprocket · 07-10-2016, 10:46 AM

I can't imagine so much water in the tank that you'd see it on the carb, yet the engine can still be run. Are you sure there's not a water leak somewhere that's spraying water at the flame arrester? Higher rpm would spray more...

JoDo · 07-10-2016, 03:54 PM

Quote:

Originally Posted by speedysprocket

I can't imagine so much water in the tank that you'd see it on the carb, yet the engine can still be run. Are you sure there's not a water leak somewhere that's spraying water at the flame arrester? Higher rpm would spray more...

While running it yesterday I had the engine completely exposed. I saw no water spraying onto it.

JoDo · 07-12-2016, 06:00 AM

Pulled off a valve cover and found water beads laying there on top of the oil. Emptied the separator into a glass jar but saw no water. Concerned, I drained my oil but found no evidence of water in the oil pan so that water must have come through the intake. Pulled the carb off and separated, the bowl was empty. Also the filter was clean. Where is this water coming from? Why does it only manifest when out on the water and not running with muffs? Could it do with the pitch of the boat when getting on plane?

Also looks to me the this gasket soaked up some water.

Kevlar7r · 07-12-2016, 03:49 PM

What is your engine temperature when operating?

I had a similar issue on a previous boat. The thermostat was stuck open and the engine was running ice cold. Water was actually condensing on the outside of the carburetor (airflow through the carb was cooling it below ambient, similar to carb icing in aircraft). I had milkshake in the valve covers and breathers, because the engine wasnt getting hot enough to vaporize combustion blowby products.

Something to check, anyway!

And that fuel vent looks to me like it could get underwater, if the throttle is chopped quickly, and the wake washes up the back of the boat. However, that is still not likely to injest a significant amount of water into the fuel.

JoDo · 07-13-2016, 04:42 AM

Quote:

Originally Posted by Kevlar7r

What is your engine temperature when operating?

I had a similar issue on a previous boat. The thermostat was stuck open and the engine was running ice cold. Water was actually condensing on the outside of the carburetor (airflow through the carb was cooling it below ambient, similar to carb icing in aircraft). I had milkshake in the valve covers and breathers, because the engine wasnt getting hot enough to vaporize combustion blowby products.

Something to check, anyway!

And that fuel vent looks to me like it could get underwater, if the throttle is chopped quickly, and the wake washes up the back of the boat. However, that is still not likely to injest a significant amount of water into the fuel.

Wow, that's interesting. I can't recall the exact temperature but always fairly cool. I'llcheck that. That aside, I drained the oil, no water. Emptied the oil filter contents into a jar, no water. Siphoned some fuel from the bottom of the tank, no water. Ran a line from fuel pump to a mason jar and cranked the engine, no water. (however that last one may not be accurate since I had just emptied my fuel/water separator which also had no water) I'm baffled. So Thank you Kevlar, I will check that.

JoDo · 07-13-2016, 04:59 AM

Another thought I'm having is exhaust. Can water be entering back through the exhaust system?

mmwjr · 07-13-2016, 12:18 PM

Quote:

Originally Posted by JoDo

Another thought I'm having is exhaust. Can water be entering back through the exhaust system?

Yes it can and the engines back pressure will suck it into the cylinder. From there it would need to leak down past the rings to get into the oil which is possible. Do you have steam coming out the exhaust?

I suspect what Kev mentioned as a more likely source from what you have described so far.

JoDo · 07-13-2016, 12:49 PM

Thanks Guys, I will update in the next few days.

JoDo · 07-14-2016, 03:46 AM

Pulled the thermostat housing off. Absolute rusty mess. Definitely needs a good cleaning and replacement. One of the check balls was stuck to the housing as well. I'm going to soak the housing with PB Blaster and then clean it good. Thermostat is out but brass sleeve is stuck, hopefully PB will help that come loose and I can put a new one in. Do I have to change the brass sleeve? It looks like it does not come with the thermostat.

B.O.A.T. means Bring on another task I guess.

mmwjr · 07-14-2016, 12:24 PM

The brass sleeve is reusable.

B.O.A.T. = Break Out Another Thousand (Boat Buck)

But I like Bring On Another Task

Kevlar7r · 07-15-2016, 02:07 AM

Quote:

Originally Posted by JoDo

Pulled the thermostat housing off. Absolute rusty mess. Definitely needs a good cleaning and replacement. One of the check balls was stuck to the housing as well. I'm going to soak the housing with PB Blaster and then clean it good. Thermostat is out but brass sleeve is stuck, hopefully PB will help that come loose and I can put a new one in. Do I have to change the brass sleeve? It looks like it does not come with the thermostat.

B.O.A.T. means Bring on another task I guess.

Sounds like the engine I was talking about. Had to hammer the old thermostat out, it was rusted in so bad.

And this was in Arizona, so getting the carb cool enough to condense water there is pretty cold. I can imagine cooler damper climate it would be even more dramatic.

Let us know how it turns out.