70hp pre-mix

[eggbert55]

1997 70 hp that is hard to and keep running after it sits for a few weeks... Been told to rebuid carbs as the gas evaporates and leaves the oil which cloges the carbs up. Now my question is if the carb rebuild works can I which it to pre-mix and disconnect the fuel line at the end of the day, then let it run until the carbs are dry and it dies to prevent this from happening again or will that create more other problems?

 

[Bosunsmate]

Re: 70hp pre-mix

You can do that, sometimes it means that one cylinder will run out earlier and run dry for a bit...
You can also buy fuel stabiliser which keeps fuel fresh for up to six months. i find storing the engine in the down position helps too

 

[eggbert55]

Re: 70hp pre-mix

The boat is at the marina so normally the motor is always down, I also keep the stablizer in the gas cause we only use it about once a month. We just bought it 2 years ago and had the starting problem from the beginning but it's getting worse. Just don't want to rebuild the carbs and have the same problem in a few months.

 

[Bosunsmate]

Re: 70hp pre-mix

Just pull the fuel line then, i do that, some people dont but i dont mind the possibilty of running lean for a very tiny period

 

[eggbert55]

Re: 70hp pre-mix

It has the VRO fuel/oil pump... wouldn't it keep pumping oil but no gas and make the problem worse?

 

[boobie]

Re: 70hp pre-mix

Yes it would. How's it run and idle after you get it running ??

 

[xjdriver]

Re: 70hp pre-mix

Now im no expert here, but im pretty sure 2 cycle oil wont clog carbs up. It should just mix back in the gas when you prime it.

 

[boobie]

Re: 70hp pre-mix

If you get enough oil in the carbs the mtr won't start. Some VRO mtrs had this problem after sitting.

 

[eggbert55]

Re: 70hp pre-mix

Smokes a lot when I first get it running until the carbs clean out, then it runs and idles great. Only problem is the hard starting once it sits for several weeks. I hope the carb rebuild fixes that problem, I'm just trying to figure out away to prevent the hard start from reaccuring without creating another problem. Figured if I ran the carbs dry after each use that might do it. It's no fun to spend 30 minutes getting the boat running every time you go to the lake. By the way it's at the marina so can't do it before going to the lake.

 

[Silvertip]

Re: 70hp pre-mix

What is your starting procedure. Many times engine problems are blamed on the engine when it is operator error.

 

[eggbert55]

Re: 70hp pre-mix

Pasted from my previous post....Purchased pontoon boat with this motor 2 years ago was hard to start then but seems to be getting worse.
Starting procedures - pump primer bulb until firm, lift lever to about 1/4 throttle, turn key 1 notch press in for 10 seconds, and turn to start. Engine starts but only runs for a few seconds dies, it will do this repeatly. If I turn the red lever on the electric primer to manual it will run but smokes alot, as it warms up I start turning the red lever back it smoothes out and will continue to run. Onces it has continued to run it starts fine the rest of the day. If it sets for 2 weeks we're back to not continuing to run.

This is what I did yesterday....
rebuilt electric primer, checked operation and for fuel flow - good
Sprayed carb cleaner into primer lines - no clog
Fresh fuel, new primer bulb, fuel line, fuel filter
Checked compression -125 in each cylinder- new plugs with good spark
Checked fuel delivery from fuel pump - strong fuel flow with every pulse to each carb.

Still wouldn't continue to run until I turned the red lever. Once it is warm and running it idles great and no hesitation or miss even at wide open throttle.

 

[boobie]

Re: 70hp pre-mix

You're supposed to push the key in when cranking, not just 10 seconds. When it pops off and wants to quit, push the key in again in short bursts to give it more fuel. After it keeps running, stop pushing the key in. This is the correct way to use the choke/primer.