Engine won’t start

[Cortneyx23]

Hello everyone, I’m at a loss here. I bought my first boat and have yet to take it out and enjoy it once. It is a 1987 Four Winns horizon 170 with a 4 cylinder 3.7L mercruiser engine. It had been sitting for awhile when I bought it so I drained the old gas out of the tank and filled it up with new. It ran for about an hour or two and then died and had to get towed back in. Took it out again after messing with some stuff and it did the same thing, ran fine and then died a couple hours in but started back up after sitting for awhile but died again and got towed back a second time. Messed with it and thought everything was good so took out a third time. Was running great, much quieter and smoother but noticed there was steam coming in from the back and saw that the exhaust bellow had cracked. Replaced that and took it out another time. This time it died and would not start at all. I’ve replaced all of the following in the time owned:
-Exhaust bellow
-Paper filter in the mechanical fuel pump
-The screen in the inline filter behind the electric fuel pump
-The start slave solenoid
-The ignition switch
-The spark plugs but they are fouled again. Not sure if they fouled from continuous attempts to start or why it’s running rich.
-The cap and rotor in distributor and then the point delete kit was installed still no change.
-Carb has been rebuilt and cleaned.
It was serviced before I bought it and the following was replaced:
-Gimble bearing
-Shift bellows
-Drive bellows
-Exhaust bellow
-Transom seal
-Battery cable
Currently there is spark (yellow and bright), and it wants to try to start but will not run. I’ll replace the spark plugs again but want to figure out the cause for them fouling. I’m not sure if there is a fuel issue, there’s fuel getting into the carburetor. Any tips or ideas on what to try next or what could be causing it to not start and also what is causing it to die after it’s running good for a few hours. Thanks for reading and thanks for your help!!

 

[CaptnKingfisher]

Hello everyone, I’m at a loss here. I bought my first boat and have yet to take it out and enjoy it once. It is a 1987 Four Winns horizon 170 with a 4 cylinder 3.7L mercruiser engine. It had been sitting for awhile when I bought it so I drained the old gas out of the tank and filled it up with new. It ran for about an hour or two and then died and had to get towed back in. Took it out again after messing with some stuff and it did the same thing, ran fine and then died a couple hours in but started back up after sitting for awhile but died again and got towed back a second time. Messed with it and thought everything was good so took out a third time. Was running great, much quieter and smoother but noticed there was steam coming in from the back and saw that the exhaust bellow had cracked. Replaced that and took it out another time. This time it died and would not start at all. I’ve replaced all of the following in the time owned:
-Exhaust bellow
-Paper filter in the mechanical fuel pump
-The screen in the inline filter behind the electric fuel pump
-The start slave solenoid
-The ignition switch
-The spark plugs but they are fouled again. Not sure if they fouled from continuous attempts to start or why it’s running rich.
-The cap and rotor in distributor and then the point delete kit was installed still no change.
-Carb has been rebuilt and cleaned.
It was serviced before I bought it and the following was replaced:
-Gimble bearing
-Shift bellows
-Drive bellows
-Exhaust bellow
-Transom seal
-Battery cable
Currently there is spark (yellow and bright), and it wants to try to start but will not run. I’ll replace the spark plugs again but want to figure out the cause for them fouling. I’m not sure if there is a fuel issue, there’s fuel getting into the carburetor. Any tips or ideas on what to try next or what could be causing it to not start and also what is causing it to die after it’s running good for a few hours. Thanks for reading and thanks for your help!!

I bet ya a nickel you've got the same issue I've got on my 1989 170 freedom.. I had the exact problem you described and finally had the decided to pump some of my brand new gas out the tank to inspect it and lo-and-behold its mostly water now after one week and one lake outing since last refuelling. I'm getting ready to drain my tank, cut it out and replace.

Check the condition of your fuel to start.