View Full Version : Engine compartment fumes

10-04-2004, 11:21 AM
I have a 1995 ProStar 190 and with one exception, the boat is in near perfect condition, mechanically as well as visually. 516 hours on the boat, service just last month to change plugs, oil, impeller, etc. The exception is that there seems to be an excessive amount of fumes coming from the engine compartment. I run the blower anytime the engine is running now. When I open the engine cover, sometimes the toxic fumes are unbearable. This seems most prevalent when there is a full tank of gas. Does anyone have any suggestions of where I should start to track down this problem before the boat blows up?

Thanks in advance.


10-04-2004, 11:38 AM
What kind of fumes are you refering to?
Gasoline fumes or exaust fumes?
If it is gas, get it fixed and don't use the boat until it is fixed!

If it is an exaust leak, that is easy to find as the exaust will leak water into the bilge.

Sonunds like one for Jim N

10-04-2004, 11:46 AM
64097: Are the fumes gasoline vapors? I had the same problem on my '95, and found a loose fitting in the gas line leading to the TBI. The fuel line comes out of the bilge at the left rear of the engine (looking forward), and there is a brass 45 degree ell just aft of the valve cover. On mine, it was just loose enough to drip adn fill the engine compartment with gas vapors. Hope this helps.

10-04-2004, 12:10 PM
Do a visual check of the entire fuel line and also check for anything that is loose. If it's more likely to have the vapors when the tank is full, it could be a fitting on the top, or maybe the filler neck/vent. I use a 5/16" ratchet for hose clamps, mainly because slotted screwdrivers and screws suck. Use whatever socket fits. If the fuel line is leaking at one of the compression fittings or the quick release fittings, you'll need to have that repaired by a shop that makes up hydraulic lines. Or, you can order them from a MC dealer.

There will always be some fumes in the bilge, but they shouldn't be excessive. If it's becoming hard to start after it sits for more than a few hours, remove the flame arrestor, turn the key on and look at the injectors for dripping gas.

10-05-2004, 06:38 PM
In order to check the entire fuel line, do I need to remove the engine cover and rear center floorboard? The gas tank is not full, and the engine compartment does not consider to have what I would call exessive fumes right now, so it quite possibly has something to do with the fittings at the top of the fuel tank. I could not find any evidence of a leak without taking anything apart.

I noticed something else weird. I haven't messaed around with the engine much yet, but I noticed what appears to be rags in the bottom of the engine well. I think they are simply wet, as I touched one and my finger did not have a fuel smell. However, I cannot see how it is normal for them to be there. There are maybe 4 or 5 in random places.

10-05-2004, 08:53 PM
Did you recently have some work done on the boat? May have been put there during an oil change or something.

If the gas fumes aren't strong at the level right now, I would be looking at the hoses on the filler neck and the tank. You should be able to access them without much trouble. Tighten both ends of the hose.

10-06-2004, 06:11 AM
When I got my '95 (in '99), When changing the fuel-filter, I noticed that some bu++head cross-threaded the upper brass nut so bad, that almost all the threads were MISSING :eek: . Thus - it wasn't able to be tightened down much if any.

If you don't find your leak, you may want to check there also.