View Full Version : Engine Problems

06-25-2012, 07:32 PM
I have a 2004 Moomba Mobius LSV with an engine problem I am trying to diagnose. If anyone can help with some suggestions or or similar situations they have run into in the past that'd be great.

All summer and all the way through this past weekend the boat was running fine. I was doing some simple maintenance on it over the weekend and realized that the fuel filter was completely rusted so I decided to change it out. The Fuel Filter exchange went smoothly with no problems putting it in correctly. I then went back up to the lake, dropped it in the water and thats where the problems seemed to start happening. The boat would turn on fine and run idle through a no wake zone fine with no
problems but the second I got out of a no wake zone and pushed down on the throttle, the boat
seemed like it was choking. Like it wasn't getting the gas it needed to run the boat. At this point, the engine temperature gauge read around 220 degrees. So we decided to bring it back in. I called a boat mechanic to come out and look at the boat and his first thought was that maybe the impeller was bad. When he got the old impeller out, all the fins were completely missing with him only find 2 stray ones in the compartment where the impeller is held. Once he got the new impeller in, we gave it another test run. The boat got up to around 20-25mph but then got to that point where it felt like it was choking and running out of gas immediately once reaching that speed. His next thought was that the loose fins might be caught in the Thermostat. So he opened the thermostat and took it out but realized there were none in there. This time, he decided to leave the Thermostat out and we ran it again. Got the boat up to around 25mph but this time it stayed there for about 10-15 seconds before cutting out again. The last thing we did was open up the hoses and knock out those extra pieces of theimpeller out of the water hoses. After that, the boat still choked up when I reached the speed of
25mph after 10-15 seconds.

I'm just wondering if you guys have any idea what might be causing this problem. Every suggestion and idea is greatly appreciated.


06-25-2012, 07:52 PM
any chance any rust trash from old filter got in the fuel line?
either before or after the filter...

06-25-2012, 08:15 PM
if it all started after the filter replacement, then some depris must have gotten dislodged and are now clogging the injectors

06-25-2012, 08:24 PM
seems like this is happening alot this summer..as it did to mine..i also replaced my fuel filter..i then pulled my injectors and cleaned them out...i also went a further step and replaced the fuel pump ($120~) and since then no problems..ohh before i did all that i replaced my water impeller..this was end of last summer..so far this summer it has only done it once and when it did..i gave her a little wide open throttle and it cleared it out..havent had any problem since (knock on wood)

06-25-2012, 08:51 PM
i have a rattling sound from what seems to be the fuel tank area when i get below half a tank or so. boat runs fine but im afraid my fuel pump may randomly quit and leave me stranded....

for OP i would put a new fuel filter in again and maybe clean the injectors like MOTO was saying

06-25-2012, 09:04 PM
Thanks for all the quick responses. It seems like everyone is thinking along the same lines that maybe when I took off
the fuel filter and put the new one on something could have gotten in and now could be clogging the injectors. Could this debris eventually pass through the injectors and eventually out of the motor or do you think it would be something I would have to get checked and thoroughly cleaned out?

06-25-2012, 09:07 PM
It couldnt hurt to put a new filter in again, who knows maybe it was a bad one. Its worth a shot. And will definitely be looking at the injectors next since that seems to be what you guys are thinking

06-25-2012, 09:10 PM
could be..dont ask my why i bought a new fuel pump but i just installed one to be on the safe side and due to the fact i had the little extra $$ and it was an easy swap out..injectors are easy to pull out too..just dont get the rubber O rings wet with cleaner because they will deform and it will be a little hard to get back in

06-26-2012, 01:06 PM
My powers of troubleshooting lead me to think you have the wrong fuel filter. If you changed it and thats when all the running issues started then take it out, put a hose in place of the filter and run the boat again. if it runs normally you know your filter is bad.

Theres no since in speculating you have a bad fuel pump, cloged injectors or anything else if the boat ran fine last year and all you messed with in the fuel system was a filter.

Your impeller and heating issues is a completly seperate problem, the boat doesnt care about temp when it comes to fuel, it will keep delivering fuel till the computer puts it in limp mode or you lock the engine from over heating.

06-26-2012, 02:49 PM
Perhaps you could check to see if you have the filter in backwards, or the wrong filter. Since they are fairly cheap and easy to swap, just try that first. If you have EFI, I would consider disconnecting the battery, in case it went into limp mode with temp issue.

Your impeller issue is seperate from the fuel filter issue.

06-26-2012, 03:31 PM
Perhaps you could check to see if you have the filter in backwards, or the wrong filter. Since they are fairly cheap and easy to swap, just try that first. If you have EFI, I would consider disconnecting the battery, in case it went into limp mode with temp issue.

Your impeller issue is seperate from the fuel filter issue.

What kind of reaction would I get if the fuel filter was in backwards? Would it choke like this or would it not allow any gas to get to the engine?

06-26-2012, 04:41 PM
If a filter was in backwards is could cause little to no flow. Most filters are designed to flow in a specific direction. Sometimes there are check valves. The purpose of the direction is, so the filter element inside does not collapse.

If the problems started after the fuel filter change, I would be looing on the fuel side. Although it sounds like the impeller needed to be changed regardless, it does not sound like the root cause of your problem. From other peoples post, I thought the impellers were more associated with engine temperature issues, not so much driveability.

06-26-2012, 07:56 PM
why did your impeller come apart after changing the fuel filter?? I would still be looking all through your water hoses as a bad fuel filter or crap in the fuel line wont cause elevated temps. I forgot to tighten the water strainer two years ago so my impeller was dry and all the blades came off, I just took all of the hoses off and sure enough there were blades inside, installed new impeller and all was good

06-26-2012, 10:19 PM
i know my impeller went out out and blades ripped out due to the age of it..idk if i still have pics of it or not ha

06-26-2012, 10:27 PM
My Guess is thatyou are getting hot and into the limp mode. Make sure all your water cooling lines are clear. I know it is hard to get all those impeller pieces out of the lines. I had asimilar issue with mine when it was new to me.