Engine Cutting Out? Please HELP!

[Tiara 3100]

Hello everyone,

First time poster so be gentle on me!! Ok so I purchased a 1991 Tiara 3100 Open with 7.4ltr gas engines. 1200 hrs, fresh water only, marina maintained and is in immaculate condition, probably a 9 out of 10. Fuel tanks where full when I bought it and apparently where kept at full at all times since new. My surveyor water tested the boat before my deal was inked, and told me it ran as new, started right up, idle perfect, powered up nicely, smooth no vibrations, he ran it up to WOT for a moment and told me it topped out at 4500rpms right where it should apparently. He also mentioned it ran beautifully at a cruising speed of around 23-2500 rpm.

We agreed on a price and I hired a hauler to tow it approximately 5 hours to my home where I spent the last 3 weeks rigging it out. Yesterday it was hauled another 2 hours to the lake. I was quite surprised actually at how much it bounced around on the rough sections of the highway. Any how we arrived at he marina and I had the travel lift splash the boat down, after about a half hour of getting organized I fired it up, she started right away and idles perfect, we let em warm up and slowly make our way through the marina, the lake was rather rough with some heavy easterlies. We start to power up the boat and all seems GREAT!! however once we get close to 2800 - 3000 RPM (where the four barrels open) it sputters a bit and stalls......we slow down and it fires right back up and idles perfect, start to power down again and it cuts out again at the same RPM range. It is only the star board engine that is doing this. It also seems not be a tad inconsistent now at low RPM. Inconsistent may not be the right word for it but it seemed to have a real small rumble or surge... really minor & barely noticeable compared to the port side.

Our thoughts are maybe fuel related, I am going to pick up new water separators and fuel filters and clean the flame arrestor. I am wondering if the 7 hours of bouncing down the highway has stirred up some sediment in the tank??

Any thoughts or help???

Thanks!

BTW: Nice site!!

[Chief Alen]

Hello everyone,

First time poster so be gentle on me!! Ok so I purchased a 1991 Tiara 3100 Open with 7.4ltr gas engines. 1200 hrs, fresh water only, marina maintained and is in immaculate condition, probably a 9 out of 10. Fuel tanks where full when I bought it and apparently where kept at fuel at all times since new. My surveyor water tested the boat before my deal was inked, and told me it ran as new, started right up, idle perfect, powered up nicely, smooth no vibrations, he ran it up to WOT for a moment and told me it topped out at 4500rpms right where it should apparently. He also mentioned it ran beautifully at a cruising speed of around 23-2500 rpm.

We agreed on a price and I hired a hauler to tow it approximately 5 hours to my home where I spent the last 3 weeks rigging it out. Yesterday it was hauled another 2 hours to the lake. I was quite surprised actually at how much it bounced around on the rough sections of the highway. Any how we arrived at he marina and I had the travel lift splash the boat down, after about a half hour of getting organized I fired it up, she started right away and idles perfect, we let em warm up and slowly make our way through the marina, the lake was rather rough with some heavy easterlies. We start to power up the boat and all seems GREAT!! however once we get close to 2800 - 3000 RPM (where the four barrels open) it sputters a bit and stalls......we slow down and it fires right back up and idles perfect, start to power down again and it cuts out again at the same RPM range. It is only the star board engine that is doing this. It also seems not be a tad inconsistent now at low RPM. Inconsistent may not be the right word for it but it seemed to have a real small rumble or surge... really minor & barely noticeable compared to the port side.

Our thoughts are maybe fuel related, I am going to pick up new water separators and fuel filters and clean the flame arrestor. I am wondering if the 7 hours of bouncing down the highway has stirred up some sediment in the tank??

Any thoughts or help???

Thanks!

BTW: Nice site!!

At the fitting that enters the carb there is a filter remove and clean. Run it again it still doing it, then move down the fuel line cleaning every filter. the anti-syphin valve could be clogged up or the fuel pickup tube., could have a screen on it at the bottom.

Are you drawing fuel from the same tank for both engines? If not the T where it comes in to the engines might be clogged.

Last i might think of rebuilding the carb, might be clogged up with gunk. And yes jostling the tank like you did might have stirred up all the gunk in the tank you could, get that stuff out of the tank . You could stick a hose hooked up to a cheap auto 12 v fuel pump costs maybe 12 bucks at any auto store, with a 6-7 foot hose in the tank and 5-6 foot hose on the other side of the pump, and pump the water and gunk off the bottom of the tank, water is heavier then fuel will sit at the bottom with the gunk.

Pump the junk into a clean, clear container and when you see clear fuel, stop the pump pull the hose. and you can do this thru the fuel pickup hole when you check the anti-syphen valve.

[Lprizman]

Considering you had a professional survey done prior and all the hauling that has been performed,,yup sediment and or the ethanol crud has reared it's ugly head,,,,I had similiar problem on my motor,,,I changed all the lines.

I basically performed a bypass,,the one line going from the primer ball to the engined was "ethanol ized".

New filters and check the internal look of your lines. I will post some pics of my experience shortly.

Welcome aboard and Best of Luck,

Lance

[Tiara 3100]

Thanks for the quick response!

Each engine has it's own 103 gallon tank, there is a T in each line that allows for one tank to feed both engines, that T is normally closed.

Rookie question here: what should I use to clean the filter with?

I will do as you mentioned by starting at the carb and working back. I guess if it is still doing it after the filters are cleaned or replaced I could open the by-pass valve and start to draw fuel from the port side and that should tell me if the fuel in the tank is bad or if the line is clogged.

Thanks.

[Chief Alen]

Considering you had a professional survey done prior and all the hauling that has been performed,,yup sediment and or the ethanol crud has reared it's ugly head,,,,I had similiar problem on my motor,,,I changed all the lines.

I basically performed a bypass,,the one line going from the primer ball to the engined was "ethanol ized".

New filters and check the internal look of your lines. I will post some pics of my experience shortly.

Welcome aboard and Best of Luck,

Lance

No primer bulb on this boat. But a fuel water separator, maybe.

[Chief Alen]

No primer bulb on this boat. But a fuel water separator, maybe.

Nope don't toggle the switch work with the tank that feeds that motor, unscrew the fuel filter and dump in a clean container and let sit, if there is water you will see it. Just screw on a new element, can be had at any marine store bring the old one with you and make sure the rubber gasket is still on the can.

work your way back from the carb, last thing you should do is rebuild the carb if you can't get it to run right after you do what i posted in my first reply, understand?

and no you don't need new fuel hose, my hoses are close to 30 years old and the new fuel has not damaged mine one bit.

Need any more help email me !

[Tiara 3100]

Nope don't toggle the switch work with the tank that feeds that motor, unscrew the fuel filter and dump in a clean container and let sit, if there is water you will see it. Just screw on a new element, can be had at any marine store bring the old one with you and make sure the rubber gasket is still on the can.

work your way back from the carb, last thing you should do is rebuild the carb if you can't get it to run right after you do what i posted in my first reply, understand?

and no you don't need new fuel hose, my hoses are close to 30 years old and the new fuel has not damaged mine one bit.

Need any more help email me !

Ok so I shouldn't try the by-pass valve?

Thanks for your help, I'll be at the boat tomorrow and will post results.

[yottyboy]

Let's assume the worst. If the carbs are gunked up and need rebuilding, you'll pay about 2-250 each to have that done with a maybe thirty day warranty on the work. I would recommend going with new carbs at that point because you can never be sure with an old carb...some are just plain no good. A new carb such as an Edelbrock 750 CFM marine ( which is a darn fine piece of kit if you ask me) can be had at the best price on earth here. These come ready to bolt on and even have a DVD that helps explain it all.

You should replace the fuel filter elements as mentioned and also the supply hoses. If they are original to the boat they should have been replaced 5 years ago. Be sure to use only Shields Flex Acol hose or even Russell braided if you are a freak like me. In the tank there may be sediment. You will want to hire a specialist who will come and clean out the tanks removing all the gunk. Prices vary but the Marina can point you in the right direction.

Worst case scenario is $700 for new carbs, a few hundred for new hoses and filters, and if needed another few hundred for tank cleaning. Doesn't include labor.

One thing that you should do as the new owner is have every rubber part on the engines replaced; belts, water hoses, exhaust hoses, impellers, whatever. In addition you'll want new circulating water pumps, new thermostats, all new hose clamps. Replace the distributor cap, rotor, points (if equipped and condensor), as well as new spark plugs and wires. Replace every fluid: hydraulic, coolant, lube. What this gets you is a maintenance baseline. Sure they said it was maintained by the marina before. Pah! worthless info. You do not want another incident like the one you just had. Thankfully it was merely bothersome and not life threatening. Once you know that everything has been done you can begin to track regular items like oil filter changes etc. Expensive, yes! That's boating my friend.

[goinsfishin]

Sounds like you've been bitten by the ethanol bug........change the filters starting at the carb and work to the tank. Get spares for the fuel/water separator and be ready to switch it out at sea. Treat each tank with a double dose of Startron, will help reduce phase separation and clean out the entire system.

Take her out and run the piss out of it........once the bad ###### is pushed thru and contained in the fuel/water separator/filter your problems will be almost over.

Change filters again and top off with hi-test and redose with startron......run her hard again....good luck.

[Tiara 3100]

Update:

Did all the fuel filters, checked the fuel tank shut-off valve, check valve, tired running on the port tank with the bypass open, changed out the coil, new distributor cap, checked carb secondaries.

We did 6 water tests with high hopes we had solved the problem, but every time we did it died at 2500-2700 rpm. I was officially put on suicide watch fearing the worst, we where just about to go and get the compression tester we we noticed one of the fuel line hose clamps had been stepped on and the hose was basically pitched/flattened shut!!!!!!!!!! This is when the whole day turned around...... we went back out for another water test and it ran like a rapped ape!!!!!!!!!!! Very strong, ton's of power and a real treat to drive. We also managed to cristen the new Tiara with some Chinook Salmon blood !!!

YEE HAAA, live is good!!

Thanks everyone for all the advice!

Great site.