troubleshoot a high end power lose

Yes, it's OK to go to another web site, iboats.com. :grin:
 
Don't know.

She sat all winter. We just got down there last weekend to summerize her. Started up fine with a little choking. Hauled her out and she's sitting at the mechanics now for new bellows etc. Hopefully the fuel pump will do the trick. Should know in a couple weeks when we can get back down there to splash after all the hay is up.
 
I have the same issue. I talked to a guy yesterday at a NAPA auto parts. He said he had the same problem with his boat and , it ended up being a chunk of sludge in the gas tank. Probably build up from the gas ring around the edge, he said it was like a slug. SO it made since, at idle it would run fine, but when it needed more gas it would suck the "slug" up and block the fuel. SO tonight I am going to replace the anti-siphon valve and drain the gas tank and hopefully find the culprit.

If that isnt it, I may be replacing the all the gas tubing and then on down the line....

Very frustrating.
 
Posted from another thread.

I, like so many other, have experienced the dreaded power down after 30-45 minutes of tubing. It happened again this weekend.
I was pulling at 4800-5000 rpm when the throttle started backing off. It would only do about 3000 rpm (blower running the whole time).

We went into a cove and swam for an hour and a half then decide to tube some more. The first 20 minute went fine then it happened again. By chance my son opened the engine bay lid to look at the engine while we were running. It didn’t take more than a few seconds and the engine came alive. The thing shot to 5300 rpm like a rocket. It nearly yanked the person off the tube.

We ran with the cover up for a few minute then continued tubing for another 30 minutes with no problem. I looks like there is not enough air displacement in my engine bay. I thouth it was fuel related but never considered air flow. Dah.:wow: I’ll need to increase the blower or add some type of better venting.

Going out again on the 5th so I’ll keep you posted.

Update.
I've had no problem on the 5th.
progress.gif

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Interesting.

So far we've been chasing "fuel" issues when one turned out to be rusted advance weights that weren't advancing and another was lack of air of all things.

All good food for thought and something to keep in the back of one's mind when troubleshooting...
 
KRB64 said:
Not real familiar with these carbs, could there be a high speed jet thats blocked?

Any ideas?
Click to expand...

Should have investigated my gut feeling from my first post...

Finally got down to pick up the 260DA from the mechanic Friday. We slid her into the water with a new fuel pump (plus new water pump, batteries, u-joints and gimbal - which weren't related to the problem but were scheduled).

She would catch but not run. Before she'd at least run but not rev out - now nothing. A quick look in the carb shows the accelerator pump working. Pull the fuel filter/seperator and its crystal clear, no water or junk. Disconnect the shift interupter and no difference.

Our mechanic was retreiving a customers boat and came over and we deduced the carb. Took it off and he went up the hill to clean it out. Came back after a bit, put it back on and she fired right up. He said the power jet was gunked up with ethanol detritis. Screen was clean (as has been all three filters) but goo in the carb despite using Star-tron starting last year.

Took her out and she revs to 4500. GPS said 28mph with a full tank and three adults. Missed a little at first but that cleared up after a bit. Dumped in two cans of Seafoam for insurance.

The amp gauge had been "weak" for the past couple years so while we were on the shakedown cruise (yea, spring only just arrived for the Bishops...) I tested the alternator and it was in fact weak. Grabbed a new one wire one from our mechanic and then me and my brother swapped it out and now have 13.2 amps at idle!

So anyway, thats the update.
 
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Glad it sounds like you got it worked out. We just went through the same thing with both engines in our 270. Major power loss a week or so after a fill-up, boat had a hard time planing but ran and sounded fine even at idle. This ethanol is really becoming an issue as much of the Mid-grade sold at marinas is now having it. Our marina just started selling gas with ethanol without any notice, blindsiding everyone with issues - especially the outboards. I guess star-tron or marine stabil is cheap insurance with every fill thoughout the season.
 
Finally got to run her some more, the family went down this weekend. Ran a couple hours tubing etc. No miss or hesitation.

Running about 21-23 mph @ ~3,900 rpm. Thats with all the stuff for four people for a weekend...

Hope startron keeps doing the trick...

Now need to look at tuning the old prop. All the talk lately of new SS etc has me thinking...

The 350ci turns 1,500hrs in a few, want to make things easy for her.
 
Oh and btw.i have a 1964 IHC tractor with a 4 cylinder gas engine. It was eating spark plugs. Bad coil.
 
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