VST Tank Re-Install Questions

[John from Madison CT]

Rodbolt and Ray: I am about to reinstall my VST tank on my '98 Yamaha 250hp Ox66. It is all back together with new filter and gasket.<br /><br />I am about to remount her on the engine, but a few things I was wondering about:<br /><br />1. With no oil in the VST, if I just pump the primer bulb to refill the VST, won't I put in just straight gas with no oil, as the engine needs to turn the gear driven oil pump to mix in the proper amount of oil?<br /><br />2. Should I just crank the engine with the kill switch pulled so I have no spark to fill it?<br /><br />3. Does the VST pump run with the kill switch pulled?<br /><br />4. How do you recommend I refill her safely so that the proper oil/gas ratio is delivered to the injectors?<br /><br /><br />Thanks,<br /><br /><br />John from Madison, CT

 

[bigbrownbuku]

Re: VST Tank Re-Install Questions

mix a separate tank with 70:1 and prime the vst with that. dont crank to fill the tank, its kinda not what the starter was designed for. the pump will run with the lanyard off but it will only pump gas during its "prime" stage at key on.<br />just connect your 70:1 premix to the plastic nipple about 6 inches in front of the main harness boot where all the cables enter the engine and prime it from there. make sure your engine filter is empty first so you dont pump the gas that was in there thru to the vst. let it run on your premix tank for a short period, maybe a minute, then reconnect your main tank.<br /><br />dont mix the oil nipple for the fuel nipple or you will prime your oil tank full of gas. gas line is usually grey, oil is black, follow them both to be sure.

 

[rodbolt]

Re: VST Tank Re-Install Questions

hello<br /> I usually fill the system with a 50/1 premix by removing the fuel line at the engine filter intake and priming with a shop tank.. the pump wont run if the lanyard is pulled. the main relay wont close to allow 12v oin the yellow/red wire for the pump or injectors. if you crank it with the e-stop lanyard off it will test the alarm system. I always pull the stop lanyard while rigging new engines to prevent a pump"dry" run. just prime the fuel system and recconect the filter line. no need to run on premix at all.as soon as the crank starts turning the oil pump will start pumping and the system willnever know it had been into. I have also seen techs just dump the engine filter and add about1/4 oz of TCWIII and reprime the system. I also see techs simply reprime with fuel and start the engine with the oil link dissconnected and the oil pump at WOT for a few minutes. if ya think about it it does not take long to change the fuel/oil mix in the vst or it would blow up after 1 hour idling then transiting to WOT. the idle mix may be as lean as 100/1 and it takes a bit at wot to provide enough oil to remix everthing in the VST to 50/1. so at an idle for 10 min it wont make any difference on a motor that is broken in and been in service. but dont just crank it to refill the VST. but if the lanyard is pulled there will be no spark,high pressure pump or injection.which is why I reccomend pulling the lanyard for compression tests.

 

[John from Madison CT]

Re: VST Tank Re-Install Questions

I like the idea of filling the on engine clear filter with 1/2oz of oil and letting it get delivered as you crank the engine.<br /><br />Does that sound OK? It is simple.

 

[rodbolt]

Re: VST Tank Re-Install Questions

dump the engine filter, add a 1/4 oz or so of oil and prime the system with the bulb. its rather hard on the low pressure pumps when not moving fuel. <br /> dont make a simple procedure complicated. I rarely add oil to the vst after servicing unless its a special case. at a dead idle it wont need much oil. <br /> so no worres. I would rather see no oil added to the VST than refilling the VST by cranking.

 

[SJ Striper]

Re: VST Tank Re-Install Questions

Rodbolt,<br /><br />I'm the guy who bought John from Madison's Whaler with the 250 OX66.<br />We are neighbors and have been on the boat many times. We followed your guide and after installing the VST the motor ran great.<br />In the past, you had helped me with small issues with my 130 yami and I always appreciated your help.<br />If I have issues that John or I can't figure out, I will be sure to post a question to you.<br />Thanks for all your help.<br /><br />SJ.

 

[rodbolt]

Re: VST Tank Re-Install Questions

post away and all will try to help. I try to catch most but sometimes I miss them. if your going to do your own maint there are some tools that are mandatory for testing/cleaning the O2 sensor.

 

[John from Madison CT]

Re: VST Tank Re-Install Questions

Rodbolt: I cleaned the O2 sensor of my old boat(SJ Striper's new boat) about 50 hours ago.<br /><br /> After probably 500 hours of use, it was remarkably clean, but I always used Ring Free and Decarb'd the engine once per year with 2 cans of Combustion Cleaner. My oil use ratio was always under 50:1 on average too.<br /><br /> The good news is my new boat, a 25' Parker, has the same engine, only a '02 250hp Ox66 !! I'm sure I will be back for more questions on my own motor.<br /><br />John