NJ Saltwater Fisherman Forums
Boating => Mechanical Forum => Topic started by: Quadruplecccc on June 23, 2008, 08:30:44 AM
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Was slow idling around sailboats snagging bunker for a little over an hour. It was time to get going but the boat fell flat on it's face once I got her up to about 1/4 throttle. Tried many times to get her going but she would respond. I shut her down , pulled the plugs which seemed fine. Tried again, then she quit. Found some water in the fuel ,cleaned it out and tried again. Motor had som time to cool down till I got all this done. Finally got her fired up and away she went. As long as I don't idle or troll for prolonged time she is fine but when she gets hot at slow speeds it's another story. It'sa 351 windsor I/O .New water pump in lower unit, new manifolds and elbows .What else might cause this condition to occur???? HELP!! Thanks
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sounds like bad gas. did you just fill up?
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water in the fuel...
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Sounds like it's getting too hot. Need to make sure the water pump belt is tight. Do you have two water pumps? One on the engine and one raw water to bring it up to the engine.
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Did you do the thermostat with the water pump?
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should not get hot at slow speeds unless minimal coolant circulation- stuck tstat, clogged heat exch, manifold, riser (yep even when new sometimes.) Maybe one or both water pumps is not up to spec (yep also even when new sometimes)
is it raw water cooled only, or raw water to antifreeze system? Either way start at the raw water intake and work your way up to troubleshoot. Chances are it's not the antifreeze side unless it's the Tstat.
If it's just bogging off idle but not hot it is likely the carb float level wrong or stuck open (if carbed) or could be bad fuel...
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whs
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It's raw water cooled. I'm on the second lower unit water pump with same results. T-stat is a 140* temp and opens up cause motor temp never exceeds 150*. Had this problem last year once on fresh fuel. This year I had nearly half tank of left over fuel that I added fresh to. As stated I did pull about 6oz of water out of the seperator.
Nevr really gave the water pump on the motor a thought . No indication of trouble. How would I check to see if it is working properly? Wouldn't it be ovrheating on a regular basis if it doesn't work?
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Also replaced the manifolds and elbows two seasons ago. Boat is trailered and flushed after each use in salt.
Just thinking out loud here but, if the motor is getting this hot for whatever reason, would this cause the fuel to cook off before it gets to the cylinders making it buck and starve for fuel?? 5hrug
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The high rpm's could move the water thru enough to keep it cool. How far do you run on high rpm, Miles like off shore or not even 5? It may not have time to over heat. I am no boat mech, but if it was my boat, I would put the muffs on, pull a hose from the water pump or riser and see if you have water flow. Any signs of water in the oil. Best to check that is pull the oil fill cap or look at the top of the dip stick and look for white or cream color on them.
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Also replaced the manifolds and elbows two seasons ago. Boat is trailered and flushed after each use in salt.
Just thinking out loud here but, if the motor is getting this hot for whatever reason, would this cause the fuel to cook off before it gets to the cylinders making it buck and starve for fuel?? 5hrug
Yes it could, how dose it crank when this happens? Is it slow or normal?
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No water in oil as of yet (luckily) I run from A,H, out to Romer . Sat. I ran from Flynns to Keansburg and back with no oveheat.I think that would be close to 14 mi.
When this problem shows up she starts like a bear. Bad enough that I start to get a little worrried!
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When you say starts like a bear, do you mean hard to start or cranks slow?
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barely turns over. like it's vapor locked
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Your getting water into the cylinders - headgasket, manifold, risers....
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OK if it hard to crank( does not spin) then if you let it sit for awhile and then it spins and starts(runs) and you do nothing but let it sit.
Then you have one of two things going on.
1: The engine is overheated. Have to find why the water is not going thru the engine. One thing that can happen but not common is the impeller on the main engine water pump is loose on the shaft and only spins while the engine is at high rpm.
2: Your battery is not charging. If an alternator is not working. (loose belt, regulator or just no good) and you have a good battery the charge on the battery will come back after sitting and crank the engine.
It sounds to me you are dealing with #1
If it was a cracked riser or bad head gasket most but not all times you would get water on top of the piston and it would make a load thud when you try to crank it and the it would not spin. You need to check the water flow. See if you can in stall a water pressure gauge to check it. Or pull off hoses one at a time to see where you lose the water. BE CARFUL YOU DON’T GET SPRAYED WITH THE HOT WATER.
Hope this helps.
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I was thinking about this. Are you sure you don’t have a raw water pump? It should be belt driven and may look like a power steering pump. I don’t know a lot about I/O’s but I pretty sure the out drive just has water intake ports. I think your problem is in the water system where the water is not moving. Do you have a water temp gauge on the boat and does it have a carb or fuel injection?
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Motor is carbed with a new 2bbl holley. Lower unit has a water pump with an impeller which was just seviced. Motor has a water pump onthe front similar to one you would see on a car or truck. Does not have a pump looking anything like a power steering pump on it. I'm thinking that the pump on the motor is used to circulate the water that the external water pump is sending up. I'm sort of leaning toward a bad water pump on motor or a clogged intake that will not allow propper flow to keep it cool. What do you think on this?
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Temp gauge works. I whatch it climb as the motor warms. It climbs to about 150* and holds there.
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You need to find out if you water at the temp sender when this happens. If there is no water at the sender you are not getting a good reading. 150 seams cold, that makes me think you dont have water there.
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Well, it's only supposed to have a 140* thermostat. That being said, I don't believe it should go much higher than that , should it??
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Temp should be good. When this happens and you get the 1/4 throttle thing, does is break up or run good up to the 1/4 throttle?
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What year is this engine and is it EFI or carb?
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I'm telling ya, water.....
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I'm telling ya, water.....
Sound like it but if he has water at the temp probe and it's @ 150 its not the water. I am think a water leak that is small enough not to make a differance at high rpm.But if that was the case the temp guage would go up. May be a bad temp gauge also.
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good up to 1/4 throttle. at that point it falls apart. 76' motor w/carb
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Was slow idling around sailboats snagging bunker for a little over an hour. It was time to get going but the boat fell flat on it's face once I got her up to about 1/4 throttle. Tried many times to get her going but she would respond. I shut her down , pulled the plugs which seemed fine. Tried again, then she quit. Found some water in the fuel ,cleaned it out and tried again. Motor had som time to cool down till I got all this done. Finally got her fired up and away she went. As long as I don't idle or troll for prolonged time she is fine but when she gets hot at slow speeds it's another story. It'sa 351 windsor I/O .New water pump in lower unit, new manifolds and elbows .What else might cause this condition to occur???? HELP!! Thanks
Have to get back to the original post. You idle along for an hour, take off and it falls flat on its face. Tough to crank over when hot. Eventually crank and starts when it cools down some. Right?
Like I posted earlier, I'm thinking you have water intrusion into the cylinders. Loading up at idle (when you have max pressure from the O/D pump) and its unable to burn water off when you hit the throttle.
When were the manifolds and risers done? You say "new". First time on the water with the new parts? I'd check those gaskets closely, water is getting in those cylinders somehow.
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Does it have points? If so check the coil, maybe be overheating. Also check the timing @ idle, full throttle and when this happens. The capacitor maybe overheating.
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Was slow idling around sailboats snagging bunker for a little over an hour. It was time to get going but the boat fell flat on it's face once I got her up to about 1/4 throttle. Tried many times to get her going but she would respond. I shut her down , pulled the plugs which seemed fine. Tried again, then she quit. Found some water in the fuel ,cleaned it out and tried again. Motor had som time to cool down till I got all this done. Finally got her fired up and away she went. As long as I don't idle or troll for prolonged time she is fine but when she gets hot at slow speeds it's another story. It'sa 351 windsor I/O .New water pump in lower unit, new manifolds and elbows .What else might cause this condition to occur???? HELP!! Thanks
Have to get back to the original post. You idle along for an hour, take off and it falls flat on its face. Tough to crank over when hot. Eventually crank and starts when it cools down some. Right?
Like I posted earlier, I'm thinking you have water intrusion into the cylinders. Loading up at idle (when you have max pressure from the O/D pump) and its unable to burn water off when you hit the throttle.
When were the manifolds and risers done? You say "new". First time on the water with the new parts? I'd check those gaskets closely, water is getting in those cylinders somehow.
You would think he would see water when he pulled the spark plugs if he had water in the cylinders. If he didn't pull the plugs and cranked it the water would leak by the rings and be in the pan.
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Not necessarily. Water will pool in the riser or manifold and not get sucked into the cylinder until the engine is under load.
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Not necessarily. Water will pool in the riser or manifold and not get sucked into the cylinder until the engine is under load.
That possable but I would think and don't know for sure. You would think at some point the water would get in the cylinder. Then it would lock up. The thing that bothers me is the 1/4 throttle thing.