Is there an easy way to do this?

[Tom Foley]

Had a similar situation with an airplane . Debris never showed up in the filter but there was a little piece of the rubber stopper that was intermittently clogging the pickup tube in the tank . Had a dead stick with no airspeed ....you know the rest . pull the tanks and check them now .

 

[Paul Dorchak]

Make sure nothing is pinched when you install the cowling also.
Best bet is in the fuel tanks.

 

[FloridaScaleBoater]

The way to check a tank is to:
Fill it up completely and DONT PUMP IT DRY, BUT let it siphon into a jug and watch for bubbles and it should siphon almost dry if not you may have a crack in a brass tube or rubber leaks with plastic tanks.

Also look for water leaks. Use a large syringe and push water in the water line at the disconnected water line with finger over the final exit tube. Push under pressure.

Had a somewhat a similar problem at the Cincinnati race recently and it was a water leak.

I recommended the siphon test last time HJ mentioned he had had problems with suspected fuel draw issues.
I can only assume it was not done??

 

[Terry Keeley]

Okay guys, I'll answer each of your questions separately:

• Sam, the plugs looked fine and , with one exception, lit right up when an igniter was applied
• Terry, it's never had one and never had an issue before though I do have one I will try this weekend
• Don, the engine has only got maybe 15-20 engine starts on it total, including this past weekend so they "should" be still good. I'll be using a different engine this weekend as the one I ran last weekend had the upper carb screw break on me. Ended up borrowing a front plate to keep running that I have to return so, if the engine does the same thing, I can assume it has to be a fuel issue.

I've had flakes of carbon from the pipe make their way into the tank and stick in the needle.

Not sure if it's been mentioned but to clean the pipe put it in a pot with antifreeze and heat it up, a cheap hot plate outside works well.

 

[FloridaScaleBoater]

OMC Carbon Guard will also break down carbon, varnish & sludge.
Used to use it when Castor was prevalent in fuels, would melt the brown tarnish/varnish right off of engine cases.

 

[David Ashcroft]

But he did run at a lower elevation (1200ft )
the week before. With the change in elevation, the air is thinner...
less volume of air.

Taking out a thin shim may be all it takes to compensate for the change.
Or prop down a little bit..

As elevation drops air becomes more dense..
My area is pretty much sea level so perfect conditions for me..

 

[Hydro Junkie]

But he did run at a lower elevation (1200ft )
the week before. With the change in elevation, the air is thinner...
less volume of air.

Taking out a thin shim may be all it takes to compensate for the change.
Or prop down a little bit..

Actually, you got it backwards

• Irene Rinehart Riverfront Park is at 1500ft, race was two weeks ago with a temperature of 85 degrees
• Gissberg Twin Lakes Park is at 113ft, race was last weekend and temperature was 75 degrees

The way to check a tank is to:
Fill it up completely and DONT PUMP IT DRY, BUT let it siphon into a jug and watch for bubbles and it should siphon almost dry if not you may have a crack in a brass tube or rubber leaks with plastic tanks.

Also look for water leaks. Use a large syringe and push water in the water line at the disconnected water line with finger over the final exit tube. Push under pressure.

Had a somewhat a similar problem at the Cincinnati race recently and it was a water leak.

I did that, believe it or not, by accident. When I was working on my engine, I had inadvertently left the fuel line in the bottom of the boat. When I went to reinstall the engine, I found the second 10 uunce tank was half empty and the forward part of the engine bay was filled with fuel. I'm assuming it was partially due to the fact the rear of the boat was propped up like in the picture above

50 is pretty fat for a 67. Like Doc said look for those bubbles. You can still pump them dry and still have a leak. When the run came back, was the second tank full. I have also had water lines that got a small piece of tubing blocking the line. The chunk of tubing got cut off while pressing it on to the hard water line.
Mike

Front tank never got below full, rear tank was always the one that showed a lower quantity. When the engine was disconnected from the fuel line, the rear tank was the one that showed a reduced quantity when fuel ran into the engine bay

 

[Tom Foley]

Are the tanks plastic or metal ? I missed that if it was posted . If plastic remove the tanks and inspect / fix / replace . I know it may suck but you have to check it out .

 

[Norm Doerr]

All very good suggestions from some solid experienced racers/boaters. I would take all of that as part of the plan. Also suggest to run a tank of fuel from a fresh new jug.

 

[FloridaScaleBoater]

Actually, you got it backwards

• Irene Rinehart Riverfront Park is at 1500ft, race was two weeks ago with a temperature of 85 degrees
• Gissberg Twin Lakes Park is at 113ft, race was last weekend and temperature was 75 degrees

I did that, believe it or not, by accident. When I was working on my engine, I had inadvertently left the fuel line in the bottom of the boat. When I went to reinstall the engine, I found the second 10 uunce tank was half empty and the forward part of the engine bay was filled with fuel. I'm assuming it was partially due to the fact the rear of the boat was propped up like in the picture above

Front tank never got below full, rear tank was always the one that showed a lower quantity. When the engine was disconnected from the fuel line, the rear tank was the one that showed a reduced quantity when fuel ran into the engine bay

Front tank, rear tank really doesn't convey how your boat is setup.
Need to know main feed tank and its location.
Second tank location.
Plumbing, fuel tube routing.
You said you had made a "boo boo"
& did a siphon test, which tank was left with 1/2 fuel? Main/feed tank?
Did it stop siphoning on its own? Or did you stop it?

 

[Hydro Junkie]

Rick, the fuel set up is a pretty much straight forward series set up. From pressure tap on the pipe to the carb is as follows:

1. Pressure tap
2. Pressure line
3. Rear tank
4. Front tank
5. Fuel delivery line
6. Carb fuel inlet fitting

The tanks are mounted under the deck on the left side, side by side, with a large line connecting them. The tanks are both Sullivan slant 10 ounce so there's no hopper/sump tank. The forward tank performs that function as well with the tanks located beside the tuned pipe's forward end.
As for the accidental siphon test, it was the rear tank that was half empty so, as fuel ran into the engine bay, the rear tank was feeding the front tank. Can't answer the other question since I wasn't really looking to see if fuel was running out of the fuel line.

 

[ALLAN YUEN]

Can show pics at engine and tanks area so will find solve

 

[FloridaScaleBoater]

Rick, the fuel set up is a pretty much straight forward series set up. From pressure tap on the pipe to the carb is as follows:

1. Pressure tap
2. Pressure line
3. Rear tank
4. Front tank
5. Fuel delivery line
6. Carb fuel inlet fitting

The tanks are mounted under the deck on the left side, side by side, with a large line connecting them. The tanks are both Sullivan slant 10 ounce so there's no hopper/sump tank. The forward tank performs that function as well with the tanks located beside the tuned pipe's forward end.
As for the accidental siphon test, it was the rear tank that was half empty so, as fuel ran into the engine bay, the rear tank was feeding the front tank. Can't answer the other question since I wasn't really looking to see if fuel was running out of the fuel line.

Did you only loose 1/2 of the rear tank?
Front tank was still completely full?
Or completely empty?

 

[Hydro Junkie]

Front tank full, rear tank down half venting through the pipe which was open at both ends since the engine was out of the boat

 

[Mike Hughes]

All very good suggestions from some solid experienced racers/boaters. I would take all of that as part of the plan. Also suggest to run a tank of fuel from a fresh new jug.

This one has got quite a few of us in the past. Me included. Add also a plug that lights but has a small leak on the seal. Will run like crap but change the plug and bingo, problem solved.

 

[Grimracer]

Something to ponder when it comes to brass fuel line..

If its soft brass it will develop cracks MUCH sooner then hard (annealed) brass tube.


All the tanks I built (Power Surge Racing Products) were using hard brass tubing.. (some are still working some 15 years later)

Grim

 

[Tom Foley]

My bet is on floating debris in the tank due to degradation of the rubber stoppers or green mung from the corroding brass tubes . Start a poll but dig in and pull the tanks !

 

[Rick Sowell]

has this boat ever run both tanks near empty?
are the tanks set up with the pick-up line in the correct corner of tank?

 

[Hydro Junkie]

Guys, I want to thank you all for the suggestions you have all given me so far. Unfortunately, my job is limiting my options so, for today anyway, I'm going to be:

• pulling the back plate off the engine and replacing it with one off another one of my engines that has a bad head on it. Would have just replaced the head but the bearings feel rough and it is very noisy, even without a glow plug in it
• Flushing out the pipe and muffler with IPA and Brakleen

Was seriously "torqued" at the LHS on my way to work. Needed to buy:

• some blue Locktite, out of stock at the supplier(found a big 1.2 ounce bottle of Permatex Blue Threadlocker for $30 at a NAPA a few miles away)
• some brass tubing to rework the fuel tanks, again, out of stock at the supplier so the tanks will have to wait. I do have some "multifuel" rebuild kits but the tubes are too short to work for the pick ups.

Rick, to answer your questions,

• yes, I've run the rear tank dry and was close to empty on the front(feed tank) several times over the years.
• yes, the pick ups are in the left rear corner when the tanks are in the boat

This brings me to a few questions.
For Grim... Where did you get the hard brass tubing?
For Mike Hughes... You recommended SS tubing to someone for cooling lines. Where did you find it or do I need to order it from K&S?
Would I be better off having a single metal tank made up for it?

 

[Tom Foley]

KS has hard brass tube . Heat red to anneal for bending . Yank the Tanks buddy !!