View Full Version : Vapor Lock????

07-09-2011, 04:13 PM
So I took my Carburated 1990 190 out last night for a couple of sessions.. On the way back to the ramp I noticed a slight loss of power... Felt like water in the gas ect.. The boat would idle and rev fine it was just at full throttle.. Anyhow I drained the tank this winter.. put in a new screen on the carb, filter in the seperator and filter in the fuel pump.. I took the seperator off to check it for water.. Poured it in a class and nothing.. I then checked the fuel bowl under the pump.. Same thing gas looked fine nothing.. Also the screen was clean up top on the carb.. I went ahead and then gapped all new plugs and threw them in.. Take the boat to the boat ramp to check things out and the thing would not crank... Its wanting too but it wont.. I threw some ether down the carb and she will come to life but as sooon as I let go of the key she stalls... Any idea on what this could be? Has anyone had any Vapor lock experiences??

Thanks in Advance for any tips...


07-09-2011, 04:44 PM
I wouldn't think vapor lock would be an issue when the engine is cold. I bet you need a fuel pump.

07-10-2011, 06:00 AM
I agree with "kevkan" and look at your fuel delivery system. Vapor lock occurs as a result of the fuel vaporizing from excessive heat prior to the delivery into the carburetor.

07-10-2011, 08:28 AM
Well my fuel pump is 21 Years old... However I also didnt fill the seprator up with gas before putting back on after checking for water.. I am hoping it is just a air pocket.. i am going to pour some gas in the carb this AM and then if that dosent keep her going its definietly the pump...

07-10-2011, 09:03 AM
not vapor lock...have experienced it the hard wayon a 98 degree day on lake....motor hot and motor compartment even hotter.

07-10-2011, 11:44 AM
Well its definietly not getting fuel.. New pump from DIM will be ordered in the AM.. I picked up a new coil today just in case... Man I hope I get this thing going by Friday.. We rented a Houseboat for the weekend and everything...

07-10-2011, 05:31 PM
Put the new Coil in and still no crank.. It will pop in the begining but then the motor just turns over.. I went ahead and removed the fuel pump to save some time.. Here is my question... Its a Mechanical Fuel pump.. I pushed the arm down and a little gas and suction came out which tells me its OK.. You can push down the arm everytime and you cand here it and feel it blowing air.. Before I throw down a $100 on a Pump what does everyone else think? I will say when I removed the pump that ZERO Gas came out of the line from the carb down... THAT tells me it was the pump... Need help... Anyone?

07-10-2011, 09:07 PM
A fuel pressure guage is the best way to test your old pump. Pump has to be in place, remove fuel line going to carb and crank the motor over with coil wire grounded to block so it won't start. (use a jumper wire for this)

Do you have a good supply of fuel coming from the tank to the pump? Make sure nothing is blocked there also.

07-10-2011, 09:15 PM
Getting fuel from Tank then to seperator and up to pump...

07-11-2011, 11:47 AM
Update talked to Vince at SKIDIM and he recomended I put the lower fuel line from the pump in a gas can and see if she would start before ordering a new pump... I put the pump back in and I did that and she fired right up... Took her down to the ramp to see if it was just a deliver hicup.. Boat fired right up.. rand great for 10 seconds then died.. I took the gas line off the seperator from the tank and it was bone dry... Seems like a delivery problem from the tank... Its a 1990 So I am going to dig in there and check it all out... Thanks Vince for saving me $100 I greatly appreciate it...as well as the knowledge...

07-12-2011, 02:35 PM
Turned out to be a siphon valve on the tank........