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1998 Air Nautique 351 HO - Carbed 290 HP
I purchased this boat in March, it was stored in a heated garage and we lake tested it on a 60 degree day and the boat ran great. I took it home, put in my unheated garage and winterized it.
We used 4 or 5 times through May, June, and July. The boat ran good, was harder to start after it ran for a while, throttle had to be held wide open (flooding issue?). While cruising across the lake around 38 mph, the boat started slowing losing power. It had done this to me one time before on the way to the dock and I backed off it a bit, but didn't really think much of it as we slowing down anyway as we came into the buoys. This time however I started seeing some smoke come from engine compartment, we immediately shut it down and towed it in. The engine did not get real hot, I think I saw maybe 180-200 and that was after the engine was shut down without letting it idle down and allowing water to continue to cool it. Oil looked fine, no water in it and clean.
I took it home and started it again, and it did not sound good, I had a buddy look at it and he noticed the exhaust manifold gaskets were leaking, which was producing the extra sound and putting some smoke in the engine compartment. Ordered new manifold gaskets from skidim as well as bolts, replaced them (was sure to drain water from manifolds before removing them). Boat started up and sounded a ton better as it was not losing exhaust out the manifolds, but had a tapping sound on the right side of the engine (facing from front). Pulled the plugs and the 2nd cylinder (right side from front of engine), had noticeable metal shavings on plug and compression tested only revealed 30lbs, while the other cylinders were 130 to 140. Boat only had 500 hours on it.
I have a reputable auto shop that is going to rebuild it. My 2 questions are:
What year of 351w engine would this be considered in order of getting the right rebuild kit?
Any idea of what happened? I only put 10 hours on the boat, so I am unsure if there was something done prior to me buying the boat. I just don't see what factor would have caused this, but I am far from a mechanic. This is my 3rd nautique, and had such good luck before, but I have been diligent about maintenance. I want to make sure I am not missing something to prevent this from happening again. 500 hours seems low for this motor to be rebuilt.
Thanks in advance!
I purchased this boat in March, it was stored in a heated garage and we lake tested it on a 60 degree day and the boat ran great. I took it home, put in my unheated garage and winterized it.
We used 4 or 5 times through May, June, and July. The boat ran good, was harder to start after it ran for a while, throttle had to be held wide open (flooding issue?). While cruising across the lake around 38 mph, the boat started slowing losing power. It had done this to me one time before on the way to the dock and I backed off it a bit, but didn't really think much of it as we slowing down anyway as we came into the buoys. This time however I started seeing some smoke come from engine compartment, we immediately shut it down and towed it in. The engine did not get real hot, I think I saw maybe 180-200 and that was after the engine was shut down without letting it idle down and allowing water to continue to cool it. Oil looked fine, no water in it and clean.
I took it home and started it again, and it did not sound good, I had a buddy look at it and he noticed the exhaust manifold gaskets were leaking, which was producing the extra sound and putting some smoke in the engine compartment. Ordered new manifold gaskets from skidim as well as bolts, replaced them (was sure to drain water from manifolds before removing them). Boat started up and sounded a ton better as it was not losing exhaust out the manifolds, but had a tapping sound on the right side of the engine (facing from front). Pulled the plugs and the 2nd cylinder (right side from front of engine), had noticeable metal shavings on plug and compression tested only revealed 30lbs, while the other cylinders were 130 to 140. Boat only had 500 hours on it.
I have a reputable auto shop that is going to rebuild it. My 2 questions are:
What year of 351w engine would this be considered in order of getting the right rebuild kit?
Any idea of what happened? I only put 10 hours on the boat, so I am unsure if there was something done prior to me buying the boat. I just don't see what factor would have caused this, but I am far from a mechanic. This is my 3rd nautique, and had such good luck before, but I have been diligent about maintenance. I want to make sure I am not missing something to prevent this from happening again. 500 hours seems low for this motor to be rebuilt.
Thanks in advance!
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