Motor Question

[IceAAA]

I have a Mercury 125 and have starting issues. Off the trailer, the motor works great. Also, when the weather is cool everything is fine. On these hot humid days though the motor doesn't want to get going after sitting in the sun. It will fire, but won't start up. I had it serviced in June and the plugs were changed. Any idea what may cause the motor to act like this in the heat? Thanks.

Andy

[leapnlineman]

Could it be vapor locking?

[IceAAA]

That is certainly a possibility. I've done some Googling and there doesn't seem to be a good fix for that problem. Some cooler weather would be my best bet. Thanks Ray.

[ProMo]

I wish i could help ya there Andy, i have the same Motor but even in the Hot weather my merc is doing fine, it does sound like a Vapor Lock issue though, wish i could help more. Something you might try though is going to www.iboats.com and go on their forum and talk to other mercury owners about operation in this heat-someone there might can help-hope so-Mo ;D

[CHIEF]

Andy

My Johnson is doing the same thing and has done it every year that I have owned it. Mine is Carbonated and I think the Gas with the ethanol is evaporating sitting in the sun. After sitting in the sun for several hours it will start but stall when I take off. I have to pump the ball and most of the time it will get going. The new guy at Dalton Marine has the same motor as mine and he has the same problem every year. He told me to hit the choke when I put it in gear.

[IceAAA]

Chief, that sounds exactly like mine acts. I did have the advice of another mechanic to rotate the idle screw a 1/4 turn to make the engine run a little richer and also pump the ball to fill the carb before starting. I'll give this a try. I guess I'm glad to hear it isn't extremely abnormal. Thanks for the link Keith. I'll do a little reading on there as well.

Andy

[hockeyruss123]

if it is vapor lock.. if it is the same for cars as for vapor lock...... remove your gas cap to release pressure take completely off... then screw back on.. and then try cranking motor... this happened to the receptionist surburban at one of my old jobs... and thats what i did and it fired right up...not for sure but its worth a try..

[RangerCliff]

Andy, I had the same problem in the summer with that engine. I had to pump the bulb as they mentioned above. Before you got it, I had the fuel line and bulb replaced to one that will better handle the ethenol. That is the only problem that I ever had with it.

[IceAAA]

Thanks for the help guys. I think the boat is telling me that it's too hot to fish. I'm definitely ready for the cooler weather. I know that will straighten it out.

[ProMo]

I guess mine is doing well because it is Garage kept and i do use stabil Marine fromula, i am so glad i have a garage. Best of luck Andy, see ya on the Trail. Sounds like those guys gave some good advice. Mo ;D

[Fletcher]

It also sound like it could be out of time just a little. As an auto tech for 20 years I have seen this problem on lots of little cars. After adjusting the timing with the car running would normally fix the problem. I'm not to sure about boat motors tho.