1997 XR6 150 hard starting and stalls

[jbaseball33]

OK so the joy of buying the boat is over and now a issue/s(minor or major, not sure). The motor won't stay running at idle (stalls) and very little power underway, not fast at all, barely gets on plane and with my wife and kids barely hit 10mph. When we lake tested it was fine now it's not(stalled a couple of times). Pretty sure boat has been sitting awhile, might need carbs cleaned but not gonna be my first option

Few things I noticed -

1. The fuel bulb won't stay hard, it should right?
2. seems like it's miss firing
3. a rubber line from the oil tank(engine mounted) has a 3way valve that isn't connected on one side, don't see any lines not connected, is that for vacuum?

Things done after issue - replaced fuel line from tank to bulb, replaced fuel filter, still stalls and now no water out the back even at WOT

Here's what I've got -
1997 Mercury 150XR6, with 3 carbs
compression on all cylinders are 130#
Plug wires check good, all fuel lines inside motor look good
will stay running as long as throttle is half way

Things I'm gonna do -
1. replace bulb and fuel line to engine (bulb should be hard and stay hard?)
2. check water pump again
3. check spark in all cylinders(not sure on how to do it, w/o getting shocked)

ALL HELP APPRECIATED

 

[j_martin]

Re: 1997 XR6 150 hard starting and stalls

1. Nope. Yer sucking on it. It just shouldn't collapse.
2. If it seems like it is, it probably is.
3. That's a valve to let air in if the line from the boat tank gets pinched or plugged. It'll let the motor get oil from the engine reservoir for about a half hour while the alarm is sounding. The one line just dangles near the starter.

You check for spark with a spark gap tester.
Check for fuel delivery. Fuel pump kit is probably needed. 20 bucks and an hour of your time if you're slow.
Check for contaminated fuel, as in water in the fuel.
Check/replace the fuel filter.

 

[CharlieB]

Re: 1997 XR6 150 hard starting and stalls

Each carb is actually two carbs sharing a housing, each side has its own brass drain plug.

With the motor level and NOT running, using and appropriate container, remove each plug, one at a time, draining the fuel into the container so you can look at it. If there are any 'beads' of water laying on the bottom your fuel tank is contaminated.

j_martin's posting show a great spark tester we like to use, connect each spark plug wire to the tester, adjust the gap to 7/16, attach the ground clamp to the motor and crank and see if each cyl is sparking. If you leave the spark plugs out it saves a lot of wear and tear on the starter and battery.

Repost your findings.

 

[jbaseball33]

Re: 1997 XR6 150 hard starting and stalls

so I replaced all fuel lines and bulb and still same issue, gonna try the carb thing, do you guys know if they make something to clean the tank or fuel pick up unit

 

[j_martin]

Re: 1997 XR6 150 hard starting and stalls

It's called hard work. You drain the tank best you can, then pull it so you can toss it around. Pure isopropyl alcohol, or maybe E-85 fuel to get the water, followed by a little acetone to get the alcohol and residual water.

If there isn't any water in the carbs, and the primer bulb doesn't collapse flat, all that is good to go. Check the fuel pump and filter.

 

[jbaseball33]

Re: 1997 XR6 150 hard starting and stalls

well dropped the boat off to have it looked at, with my lack of tools going deeper is just silly right now. I installed new plugs and finally got all the gas out, pump in 10 gallons of high test and 2oz of sta-bil, Tech is going to rebuild carbs, check spark and let me know. However I noticed that a fitting coming off the head cover (where spark plugs mount) there appears to be a vacuum fitting that has space for 2 lines but only one is connected, also on the oil tank mounted to the motor is a threeway as well with only 2 lines, does that oil tank need to be connected to the heads for vacuum?

 

[j_martin]

Re: 1997 XR6 150 hard starting and stalls

Like I said before........nope.

 

[jbaseball33]

Re: 1997 XR6 150 hard starting and stalls

Like I said before........nope.

i missed that, thanks for the follow up, going to get a manual tomorrow and start looking through it, hard to trouble shoot not knowing.

 

[j_martin]

Re: 1997 XR6 150 hard starting and stalls

i missed that, thanks for the follow up, going to get a manual tomorrow and start looking through it, hard to trouble shoot not knowing.

You got that one right.

 

[jbaseball33]

Re: 1997 XR6 150 hard starting and stalls

Well like I said I dropped the boat off and it's running now, they rebuilt the fuel pump and clean the carbs(he said they were nasty), the mechanic took for a test run and said it feels like it has prop slippage (not pushing the water), is that something to worry about or should I be ok for now? I don't fish tournament so not worried about a hole shot, just need to pull tubes, take me fishing and other family things. The prop is a laser II 23p. Gonna mark the gears to make sure it's not a spun hub.

The next issue is the tach on the dash is messed up, jumps all over, will try to clean but if that doesn't work I can replace with any tach right?

 

[j_martin]

Re: 1997 XR6 150 hard starting and stalls

Well like I said I dropped the boat off and it's running now, they rebuilt the fuel pump and clean the carbs(he said they were nasty), the mechanic took for a test run and said it feels like it has prop slippage (not pushing the water), is that something to worry about or should I be ok for now? I don't fish tournament so not worried about a hole shot, just need to pull tubes, take me fishing and other family things. The prop is a laser II 23p. Gonna mark the gears to make sure it's not a spun hub.

The next issue is the tach on the dash is messed up, jumps all over, will try to clean but if that doesn't work I can replace with any tach right?

On that one, the tachometer is driven from the alternator stator, connected at the rectifier on one of the yellow wires. Automotive tachometer won't work.


A spun hub will usually not even allow you to get going very well. A damaged prop will usually slip quite a bit as it's just stirring the water instead of smoothly screwing through it. It's well worth while to have a near perfect prop on that high performance engine.