New member with 260 Merc issues...

[jasonhart]

Great information on this site! You all have been a ton of help so far. I have a 1984 23ft Chris Craft Scorpion with a 260/350 merc. Only 250 hours on this girl. First boat we've owned and love it...up until this spring. Runs great for 15 to 20 mins and hesitates then dies. Wait half an hour and she starts right back up. Slowly working my way through everything to try and pinpoint the problem. Went through fuel system, replaced thermostat(haven't got it back out yet). I hope that's the problem, be a cheap fix. Still going to check the cooling system per mercruiser manual. Had a new Alpha 1 outdrive put on this spring, hoping it's not the water pump impeller. Here's a couple photos of the old girl. Thanks for the help!

 

[QC]

Re: New member to iboats...

Re: New member to iboats...

Welcome aboard Jason. I am going to move this over to the Mercruiser section as you'll get more focused help there. Would not really be a specific Chris issue. There are some Scorpion fans here. Good luck with her. Nice ride, nice dog too for that matter.

 

[jtmarten]

Re: New member with 260 Merc issues...

Could be a fuel supply issue.
When it dies, see how hot the coil is getting, it may be on its way out.

 

[QC]

Re: New member to iboats...

Re: New member to iboats...

Why the focus on cooling system? What's the temp doing? I don't think it's related to the shut down issue, but more info is always good.

 

[jt2004]

Re: New member with 260 Merc issues...

Ya I agree with QC I would not bother with the cooling system unless your gauge shows you're overheating, sounds like a fuel supply issue, check and make sure your fuel lines are not in an area that is getting hot to rule out vaporization. ever try running with the hatch open get cool air in there and see if that made a difference?

 

[jasonhart]

Re: New member with 260 Merc issues...

Wow! Lots of responses, thanks guys. The coil has been swapped out jtm, at the lake, and that wasn't it. If it is a fuel issue why would it run and idle fine until it got up to temperature and then die? I haven't tried to keep the cover open while running. Ya, the dog loves the boat as much as us!
I replaced plugs, wires, coil, cap, rotor, and sensor. What really bugs me is that the bost has run fine the last 3 years; as soon as I dump some money in it I get problems. I really feel like it's something minor, just need to find it before I pull all my hairs out! This forum is so much help, thanks you guys.

 

[jasonhart]

Re: New member with 260 Merc issues...

Thanks QC for moving my post, not a Chris issue, more of a merc issue. Just gonna keep chipping away at it. Found a link to merc manual #9, got just about everything a guy could need in there. The guage doesn't show that it's getting overly hot...160-170 and that's when it cuts out. But there's no guarentee that my temp gauge works. Going to buy an IF thermometer and see what it really reads.

 

[QC]

Re: New member with 260 Merc issues...

It literally will not start or run in this condition? If not, try running it out of a remote tank. BTW, I don't think this is the issue, but have you changed your fuel filter recently?

 

[sailsmanship]

Re: New member with 260 Merc issues...

Had the same problem a couple years ago, drove me nuts. Check to see if you have a fuel filter/sock in the tank. Found out that when running great for a while, sediment would build up on the sock and cut off adequate fuel flow to the carb. Sit for a while and the crud would drop off and start and run fine again until it sucked enough back on again to cause the problem again. Changed the filter/sock and have never had the problem since.

 

[jasonhart]

Re: New member with 260 Merc issues...

Yes QC, changed the fuel filter. Could be a million things. It runs fantastic, get 48-49mph with 13 3/4" 21 pitch prop. Just quits after 15 20 mins. Wait half hour and all is good again. I need to pull all that stuff out 0of the fuel tank and make sure nothing is plugged. A guy could go for awhile before he figures it out...especially on a 26year old boat.

 

[FreeBeeTony]

Re: New member with 260 Merc issues...

How about the fuel tank vent being clogged?
tryt running it w/ the fill cap removed.........or on a seperate tank as suggested above.

 

[jtmarten]

Re: New member with 260 Merc issues...

How about the fuel tank vent being clogged?
tryt running it w/ the fill cap removed.........or on a seperate tank as suggested above.

+1

Make sure your fuel line isn't in close proximity to too much heat, may be vaporlocking.

 

[commander315]

Re: New member with 260 Merc issues...

I have twin 260 Merc's from the same year and every other season they have overheating issues. try the water pump impeller. (Believe me I had to change mine so many times Ive become a pro at this) Hopefully its not something thats a bigger deal like the risers of manifold...and yea..vapor locking is another possibility

 

[Bondo]

Re: New member with 260 Merc issues...

Just quits after 15 20 mins. Wait half hour and all is good again. I need to

Ayuh,.... What ya Need to do is, Diagnose the issue, When it quits....
At That point, Check for Fuel,+ Fire.....

You're just bouncing hither 'n tither, Throwing parts at it, Hoping for the Best....

 

[jasonhart]

Re: New member with 260 Merc issues...

Did some more checking at the lake last sunday. Definately the inpeller pump. Fixed wiring on temp gauge and got up there. stopped the boat and started pulling off hoses. Was very little water in manifolds. Left hose off heat exchanger and had wife start it, a litte water came out but was full of air bubbles. One good thing about it is that White's Marine here in Casper, Wy has to do the fixing...all under warranty. She has a date on Monday, I will keep all informed if this is the fix.

 

[Fordiesel69]

Re: New member with 260 Merc issues...

If the engine died becuase of the impeller, you will still be stuck with some major engine work. Do a compression check to confirm.

 

[QC]

Re: New member with 260 Merc issues...

Ask lots of questions . . . unless there is a safety shutdown system (there isn't) then the impeller is not causing your shut down issue. There is an exception, and that would be if she has been so badly overheated that you've got major issues allowing water into the cylinders . . . I think that's what Mr. Diesel is trying to tell you ^^^^

You might be guilty of a common diagnostics mistake: finding one thing and atrributing it to another existing problem. It is entirely possible (probable) you have more than one issue