GT 200 not running right

ASEAudie

Seaman
Joined
Apr 30, 2012
Messages
57
Hi folks, I haven't been on here in awhile due to being overwhelmed with work. Unfortunately, now I have an issue with this 1988 V6 with the VRO (variable ratio oiler) system, I come to the conclusion that the pump was not producing enough fuel for these 6 hungry carbs. so I replaced the VRO pump assembly.
The customer took it and was not seen for a week or so, then he stops back in and said it ran beautiful in the beginning, then all of a sudden it went back to what it was doing before, which is sputtering and running like crap.
Any suggestions?
I am considering a standard fuel pump and mixing the fuel/oil manually. The customer is ok with that as well (he plans to sell it soon after).
Thanks in advance.
It is a 1988 Johnson GT 200 Model J200STLCCM
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: GT 200 not running right

You may want to check it out to see if you have any ignition problems before digging into the fuel system.
 

dehydrated

Petty Officer 1st Class
Joined
Dec 25, 2009
Messages
299
Re: GT 200 not running right

Agreed, might want to do simple spark test could be power pack, Have the carbs been serviced?
 

ASEAudie

Seaman
Joined
Apr 30, 2012
Messages
57
Re: GT 200 not running right

You may want to check it out to see if you have any ignition problems before digging into the fuel system.

Ignition is fine, has very weak fuel supply. Just squeeze the primer bulb and she perks right up.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: GT 200 not running right

When you say ignition is fine, how are you testing it ??
 

ASEAudie

Seaman
Joined
Apr 30, 2012
Messages
57
Re: GT 200 not running right

When you say ignition is fine, how are you testing it ??

511-9766 Spark Tester.jpeg This tester, but remember I was saying, when the primer is squeezed it comes to life; that is not an ignition problem.
 

d.boat

Chief Petty Officer
Joined
Sep 19, 2008
Messages
520
Re: GT 200 not running right

Have you made sure the entire fuel system up to the OMS pump (no longer called VRO) - including all lines, the pickup tube and filter inside the tank, air vents, any inline or water separating filters, etc. etc. is in good condition? And that there's absolutely no way that water or contamination is getting involved?

How about the carbs?

To me, if you've replaced the OMS pump, and the ignition system checks out, I'd think that there's a fuel problem before the pump, or the carbs?

By the way, I think you'll find that a non-mixing fuel pump isn't a lot cheaper than the one you just installed, and I can't imagine why it would solve the problem since you just installed a new fuel pump. Most people who want to pre-mix just disable the oil side of the OMS pump and disable the oil alarms, rather than installing a different pump.
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: GT 200 not running right

Get a six gal tank and fuel line and hook the hose directly to the vro fuel inlet and see what happens. This will tell you if it's the pump or the boat fuel system.
 

ASEAudie

Seaman
Joined
Apr 30, 2012
Messages
57
Re: GT 200 not running right

Have you made sure the entire fuel system up to the OMS pump (no longer called VRO) - including all lines, the pickup tube and filter inside the tank, air vents, any inline or water separating filters, etc. etc. is in good condition? And that there's absolutely no way that water or contamination is getting involved?

How about the carbs?

To me, if you've replaced the OMS pump, and the ignition system checks out, I'd think that there's a fuel problem before the pump, or the carbs?

By the way, I think you'll find that a non-mixing fuel pump isn't a lot cheaper than the one you just installed, and I can't imagine why it would solve the problem since you just installed a new fuel pump. Most people who want to pre-mix just disable the oil side of the OMS pump and disable the oil alarms, rather than installing a different pump.

I will check it more this weekend and reply back with my findings. Thanks.
 

ASEAudie

Seaman
Joined
Apr 30, 2012
Messages
57
Re: GT 200 not running right

Get a six gal tank and fuel line and hook the hose directly to the vro fuel inlet and see what happens. This will tell you if it's the pump or the boat fuel system.

Another good idea, thanks
 

d.boat

Chief Petty Officer
Joined
Sep 19, 2008
Messages
520
Re: GT 200 not running right

Get a six gal tank and fuel line and hook the hose directly to the vro fuel inlet and see what happens. This will tell you if it's the pump or the boat fuel system.

Another good idea, thanks

Yea - boobie's advice is better than mine - you can quickly and easily check the entire boat fuel system by simply bypassing it with his method. If it works, then you can trouble shoot yours.
 
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