Hi, new to the site and to boats......
I have a '97 Sea ray with the 3.0L Mercruiser engine. Bought it this spring and ran all summer. Always started easy cold, overrun on shutdown but not for long, sometimes tough to start when warm. I took her for a 4 hour run at approx 3200rom and she ran great. Next day took her out for a 30 min run and again ran like a dream.
Next start there is rainbow on the water and smelly brown smoke from exhaust and would not idle unless gas given and held above 1200 rpm. I let her warm up, which seemed to take forever and ran her a little slower than I normally would for 45 mins or so and no more rainbow or smoke when coming home and idle is fine.
Each start up is now the same with this nasty smelly gunk coming out the back. No more running
Back at the house with the boat, installed the muffs and ran fresh water through. Now have rainbows in the driveway. Temp gauge hardly moves. Pulled plugs; they are black. Compression tested all 4 holes and all looks good, 170, 175, 175, 160. Checked for spark on each plug and lead, all seem ok. Oil seems a little high on the dipstick but gives no indication of water contamination; it is still black and slippery - No milky film. I put a piece of card behind the exhaust and ran again (no water as was now shop). Residue on the card is a black sooty like substance. Idle still no good but warms up nice and fast.
Now a a dead end. Could this be as simple as a thermostat stuck open?????
Sounds like she is way too rich but have not adjusted anything. Where next? Any ideas welcome....
I have a '97 Sea ray with the 3.0L Mercruiser engine. Bought it this spring and ran all summer. Always started easy cold, overrun on shutdown but not for long, sometimes tough to start when warm. I took her for a 4 hour run at approx 3200rom and she ran great. Next day took her out for a 30 min run and again ran like a dream.
Next start there is rainbow on the water and smelly brown smoke from exhaust and would not idle unless gas given and held above 1200 rpm. I let her warm up, which seemed to take forever and ran her a little slower than I normally would for 45 mins or so and no more rainbow or smoke when coming home and idle is fine.
Each start up is now the same with this nasty smelly gunk coming out the back. No more running
Back at the house with the boat, installed the muffs and ran fresh water through. Now have rainbows in the driveway. Temp gauge hardly moves. Pulled plugs; they are black. Compression tested all 4 holes and all looks good, 170, 175, 175, 160. Checked for spark on each plug and lead, all seem ok. Oil seems a little high on the dipstick but gives no indication of water contamination; it is still black and slippery - No milky film. I put a piece of card behind the exhaust and ran again (no water as was now shop). Residue on the card is a black sooty like substance. Idle still no good but warms up nice and fast.
Now a a dead end. Could this be as simple as a thermostat stuck open?????
Sounds like she is way too rich but have not adjusted anything. Where next? Any ideas welcome....
