Logo

Engine lacks power and alot of exhaust fumes can be smelt in boat

Maka

New member
Hi
i have a Tige 2003 boat it has a 350 GM vortec marine power inboard motor that i just cant get to run correct. The motor starts and idles ok, however it lacks power.
It will only get to about 32mph and if you are towing anyone it struggles to reach 25mph when you go into a turn it loses alot of speed. There is also alot of exhaust fumes at idle that you can smell in the boat that makes it very unpleasant for the passengers especially in the back of the boat. I have checked the throttle position sensor, Map sensor and they seem to be fine. I have chenged spark plugs, fuel/filter seperator.
I did have a cracked muffler (silencer) at the engine end. It cracked just after where it clamps onto an elbow. One side of the elbow connects to a black peice of flexible rubber pipe that comes from my exhaust manifold riser and the other side of the elbow connects to my muffler, well just after that is where i found the crack. About 1/2 the circumference of the pipe had a crack. I noticed this when i seen the bilge full of water one time and noticed the water coming in through this crack. The actual first time i had this loss of power was the previous time i had the boat in the water at the end of a day sking but i did not notice the crack until the following time. The cause of the crack looks to appear that it was caused buy the hose clamps coming loose on the elbow that i was talking about before that connects the black flexible rubber hose to my exhaust manifold. When i noticed this crack i also noticed the inline muffler (silencer) was laying flat in the bottom of the boat, where as the other muffler was lying sloping down to the back of the boat. I pulled the muffler out of the boat and done a repair on it using a two pack cement like glue that i could find at the time. I know this is not ideal but its all i could find at the time (I'm in Laos and i couldnt find any fiberglass), but it seemed strong and didnt appear to leak any water. Since then the other muffler has cracked at the same place but is smaller in size and i have repaired this the same way as the other, I thought this crack may have come about from some one standing on the muffler when i was installing my ballast pumps as it had not slipped from loose hose clamps like the other, but its only a thought. Could these cracks be a cause of some sought of back pressure from when the muffler slipped the first time, Could i have got water into my engine because of the muffler slipping and lying flat(it slipped about 2" or more)? I thought if i had water go into my engine it would lock up. Have i damaged the internals of the muffler? and would this cause back pressure in the other muffler causing it to crack? Could the mufflers both be leaking still where i have repaired the crack and would this leak cause the loss of power????
Sorry for such a large thread but as i am in Laos and there is no one here to help any input would be greatly appreciated. I am determined to get to the bottom of this, i have lost alot of leisure time due to this problem.
Thanks
 
Back
Top