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View Full Version : 1986 Started Running terrable


Xjet2011
09-19-2012, 12:15 AM
Just thought I would post this in case it eventually helps someone else.

I have had an 86 Mastercraft now for 11 months and have put over 150 hours on it myself. Typically run the boat 2-3 times per week. Other than the bad gasoline issue I had with the boat on the day I purchased it I have not had a single problem with it until last Thursday.

I was being pulled behind the boat and let go. Boat circled back to pick me up and motor stalled. Motor would turn over but did not want to start. After about 15 minutes of walking the boat along shore towards the ramp we tried starting it again. Boat started up but was missing and popping. I thought it was flooded. Ran the boat to top speed and it started running great then after about 10 seconds at top speed it started running real rough and even backfiring. Limped to the boat ramp.

Took the boat home changed the fuel filter and spark plugs. Ran the boat on the water hose. Seemed to possibly be ok so back to the lake to confirm but it was not fixed. Started missing popping running terrable. I started feeling the exhaust temp on the exhaust manafolds right where it comes off the head. 2 cylinders did not seem near as hot as the others.

Ended up changing out the Distributer cap and Rotor and immediatly when starting the boat up on the Water hose the exhaust was hot on all cylinders. Took the boat to the lake and ran like a new engine again. I have ran the boat about 4 hours since and it still is running great.

Before changing out the Distributer cap I had looked inside and even wiped it with a clean paper towel. There was no visible damage or issues I could see. I really did not think changing the cap and rotor was going to fix it.

Almost feel like replacing it back with the old distributer cap and rotor to see if it goes back to running that bad but I am going to leave well enough alone.

Anyone else have this happen? Thanks Gary

thatsmrmastercraft
09-19-2012, 12:46 AM
Distributor caps and rotors are notorious for causing rough running issues. Years ago, with lesser quality materials, caps would fail and a crack would be clearly visible....not so much now. I change my cap every other year just to avoid this from happening.