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Hello,
I purchased a very nice MKV boat a couple of weeks ago. The boat is in such good shape that I couldn't pass it up. The 70 HP Yamaha motor was running on the muff in the sellers driveway and seemed OK. He said he hadn't run the boat in over a year but had put stabilizer in the fuel. He said the motor had been running strong and based on the condition of the boat I think he takes care of his stuff. When I got the boat home I've discovered that the motor is very hard to start when cold. By hard I mean nothing for 20 to 30 seconds of spinning the starter with the choke on. Then one cylinder will start to pop, than a second and suddenly it fires up and idles fine. It's probably more than a minute before it's running. I don't run the starter for a full minute but I start and stop probably 10 times before it finally catches. After its started and running you can stop it and you just have to touch the key and it starts. The easy starting will stay for a couple of hours after it's warmed up and than stopped. I haven't have it on the lake yet as I wanted to address this hard start in my driveway and not the dock. Battery is new. Compression is between 135 - 140 psi on all 3 cylinders. The electric choke is working. I've removed the fuel filter and cleaned it and I've replaced the fuel line from tank to motor as the old one was looking old. One thing that I notice is that when squeezing the bulb it never gets that hard. It almost seems like I'm priming the tank and not the motor. That's why I replaced the line. I'm going to replace the plugs but I doubt that is the cause as it runs perfect once it starts. It almost seems to me that it's losing all of its fuel as it sits and each cold start is a re-prime of the entire system? The other thing that I find sort of strange is when it's running applying the choke doesn't kill it that fast. Especially at higher RPM. It almost seems like the choke isn't entirely closing off the intakes but it looks to me like they are closing all the way. Today I'm going to get a new fuel tank and fill it with fresh high test gas before I dig in any further. In the mean time I thought I would post in case this doesn't solve things and I have to dig deeper. Sorry about the lengthy first post but I'm hoping someone has seen this before. Any advice will be appreciated. I'll update after I try the new gas and tank.
I purchased a very nice MKV boat a couple of weeks ago. The boat is in such good shape that I couldn't pass it up. The 70 HP Yamaha motor was running on the muff in the sellers driveway and seemed OK. He said he hadn't run the boat in over a year but had put stabilizer in the fuel. He said the motor had been running strong and based on the condition of the boat I think he takes care of his stuff. When I got the boat home I've discovered that the motor is very hard to start when cold. By hard I mean nothing for 20 to 30 seconds of spinning the starter with the choke on. Then one cylinder will start to pop, than a second and suddenly it fires up and idles fine. It's probably more than a minute before it's running. I don't run the starter for a full minute but I start and stop probably 10 times before it finally catches. After its started and running you can stop it and you just have to touch the key and it starts. The easy starting will stay for a couple of hours after it's warmed up and than stopped. I haven't have it on the lake yet as I wanted to address this hard start in my driveway and not the dock. Battery is new. Compression is between 135 - 140 psi on all 3 cylinders. The electric choke is working. I've removed the fuel filter and cleaned it and I've replaced the fuel line from tank to motor as the old one was looking old. One thing that I notice is that when squeezing the bulb it never gets that hard. It almost seems like I'm priming the tank and not the motor. That's why I replaced the line. I'm going to replace the plugs but I doubt that is the cause as it runs perfect once it starts. It almost seems to me that it's losing all of its fuel as it sits and each cold start is a re-prime of the entire system? The other thing that I find sort of strange is when it's running applying the choke doesn't kill it that fast. Especially at higher RPM. It almost seems like the choke isn't entirely closing off the intakes but it looks to me like they are closing all the way. Today I'm going to get a new fuel tank and fill it with fresh high test gas before I dig in any further. In the mean time I thought I would post in case this doesn't solve things and I have to dig deeper. Sorry about the lengthy first post but I'm hoping someone has seen this before. Any advice will be appreciated. I'll update after I try the new gas and tank.
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