need help 87 johnson fuel issues

hello I am new to boats and the site but I have a major issue

I have 1987 skeeter starfire with a 150 Johnson gt150 vro I bought the boat just last week knowing it had issues but thought it would be simpler to diag but i was wrong but put the boat in the water and it will beraly get on plan surging all the way until it dies then its hard fire back I sense then just have replaced the primer ball fuel filter and plugs put it on the muffs at home and asoon as you start it and start going up in the rpms it starts to sputter but if I press the choke in it starts to smooth out i just need to know where to go from here also when running it on the muffs and holding the choke in the fuel fitler seems to drain down and not fill back up quick just lost any help will be deeply appreciated

Re: need help 87 johnson fuel issues

really need some help and guidance

Re: need help 87 johnson fuel issues

Welcome to iboats. Does indeed sound like a fuel related problem or problems but best to give the motor a full health check before going any further.

Compression
Spark
Spark plug condition
Fuel delivery

Do some reading in the "Top Secret Files" at the top of this section for some great help and advice. Check some things from there out and post the results.
You will get more and better responses once we all have some more information to go on.

Re: need help 87 johnson fuel issues

While running the engine, try constantly priming the fuel hose bulb. This will force extra fuel into the carbs. If it runs ok while you constantly prime the fuel hose bulb, it's a fuel starvation problem. Could be a bad VRO pump, fuel restriction, bad anti-siphon valve, or bad fuel pickup in the tank. Check for fuel leaks in the fuel system.

Re: need help 87 johnson fuel issues

thanks for the advice I am in the middle of rebuilding the carbs and replaceing all the fuel lines and I am going to delete the vro pump is there a thread on here for the best way to delete that pump pump thanks again

Re: need help 87 johnson fuel issues

Doubt you'll find an exact description of the conversion. If you delete the VRO, you will need to revert to the earlier V6 engine fuel delivery system. It was last used the year before OMC went to the VRO type pumps. 1983. You can look at an 83 or prior V6 factory fuel pump arrangement at the factory parts diagram website: epc.brp.com. You'll note that this system is a dual pump system. Both pumps on this diagram have been superceded, part numberwise. Also, both pumps use a hose for the pulse line, connecting to a hose barb on the block. Your current VRO system only uses one hose barb. You will need to add another to the nearby blocked off port on your 87 block. FYI both pumps are the same PN, but the upper is sold as a kit, so it has a different PN from the factory.

Re: need help 87 johnson fuel issues

do you have to use both pumps why cant you just use the one and be done

Re: need help 87 johnson fuel issues

js87skeeter said:

do you have to use both pumps why cant you just use the one and be done

Click to expand...

The issue is volume of fuel delivery. The loopers like a lot of fuel pressure. I converted my 140HP V4 from the VRO to a pre-mix system with 1 pump and had no issues. I was however only feeding 4 carb's / cylinders.
If you get fuel starvation to any of the cylinders that also means that you are not getting any lubrication to those cylinders either.

Here is a link to my conversion. may help a little.

http://forums.iboats.com/johnson-ev...-mixer-photos-265363.html?highlight=pre-mixer

Re: need help 87 johnson fuel issues

If you want to run one pump, replace the VRO.

Re: need help 87 johnson fuel issues

i cant find a rebuild kit for this 87 and a new one is anywhere from 450-650 somthing i dont want to replace unless im 100% sure is the issue

Re: need help 87 johnson fuel issues

js87skeeter said:

i cant find a rebuild kit for this 87 and a new one is anywhere from 450-650 somthing i dont want to replace unless im 100% sure is the issue

Click to expand...

Likely looking at an OMS pump. Check the current pump out before considering replacing. Other option is 2 pre mix pumps.