SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: 79charger on February 08, 2011, 03:39:52 PM
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I am chasing a Overheating problem on my freshly rebuilt BBF. I only had a chance to take it out once before the season was over but the motor was running at 195 WOT and 225-230 idle . The heat proof paint even wore off my heads . I replaced the temp sending unit , my lines are not clogged so what gives ? Could my new carb be too lean and causing it to run hot , or is there away I can identify that my head gaskets were put on right with out pulling my heads???
Thanks alot
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I had a couple issues like that...First thing I did was pull the two block drains and got a grip of sand out from either side. This took a few hours of on off water while sliding a small tube in the drain to keep it moving. I also had a valley intake and all plugs showed lean. I now have bitchn nonvalley felpro. My temp wot is aprox 140 with a quick spike to 160+ back to idle then 140 again. How is your boat plumbed (headers-logs). What type of fuel pump/pressure are you at. http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html (http://www.dansmc.com/Spark_Plugs/Spark_Plugs_catalog.html)
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knowing if you have headers or logs would be some important info...however if your head gaskets are wrong the first thing i would look for it check your spark plugs...if them bastards are clean it would be a good indication that water is entering your cylinders...if that isnt enough with the spark plugs out roll the motor over by hitting the start key and see what comes out of the spark plug holes! also what i am curious about did you by any chance actually put a thermostat in, like you would with an automiotive engine? you can run a thermostat but it takes a special bypass setup to run one! i would vouch to say that 95% of us jet boaters run an open loop system with no thermostat, and everyones temps run right about the same temp...your temps are way to high! and what your mom said about checking for sand is always important, but i highly doubt that you have that issue being a new motor, but it is always worth looking into...also have you checked that possibly the feed line from the jet to the motor is not plugged with some type of garbage restricting water flow to the motor?
just some simple things to look at...i mean it is troubleshooting without any of us being there
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I have Harman Water logs .... The motor was built for a marine application . I have the fel pro intake gaskets ...I have checked the hose going from the jet to the logs ..... no thermostat, cobra jet intake . Better not be any sand in the motor lol .If it helps the paint peeled away form the heads around the exhaust port no where else . Plus look a little lean but not "clean " and no contamination in the oil ......
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my old BBF motor had the paint peeled at the tops around the the exhaust ports i really dont see that being a problem, and that motor on a hot ass day ran around 160...now if im not mistaken...some senders have different ohm reading then gauges, and that can booger up some shit as well...maybe you have the wrong sender for the guage!!! many people have the same issue with their gas guages!!!!! for instance i have auto meter guages so my sender is the one auto meter included...i have a couple of senders that have migrated from other engines, and i have labeled them to make sure i dont cross contaminate it with the sender there came with my guage, and i have made sure the one for my guage has ended up in both motors...i dont know exactly how that would affect your guage readings, but it is just another idea...if im not mistaken you can take ohm readings from both ends of the guage and the sender and find out if that is your issue...the reason i asked about your plus is the simple fact that nothing will clean an engine better than water! and why your plugs would looks so clean is from water...being lean though will definately heat some shit up!!!!! as far as that much i really doubt it!
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Are you running the valve off the pump all the way open...What about your fuel pressure/pump. Nordie made a good point about the sending units...Almost all 460's stock heads Ive seen have paint somewhat cooked around the exhaust ports. If your running logs/snails, the through bolt log is the only one to use. These are the only ones that will not leak or warp at the port.
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I have long bolts , I pulled valve off to make sure it wasnt slowing the flow down ..... guess i will keep looking thanks guy
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I run a 460 with a v drive and it too is a pain to regulate. I run the logs on separate line and dump as they require very low pressure. Then run the inlet water to the block in and thermostadt housing out, on the out lines run valves to control the flow out. I finally run a raw watere pump that puts out about 20 lbs of water pressure, this works for me. water pressure is critical.
Their are so many orfices with them together the temps change the water ends up being forced thru these fittings creating uneven flow of water. If you have a infred guage check the temps as been alluded too, the wrong sender will give wrong temps.
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Did you check to verify that your water plumbing is correct?
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Yes , pump to logs . logs to water pump cover , intake manifold to snails .....
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Yes , pump to logs . logs to water pump cover , intake manifold to snails .....
IMHO you need to verify that everything is clear of debris. It does not take much to restrict the water flow, a gauge may tell an interesting story...
How fresh is the pump?
Also, I believe most gasket manufacturers have a tab at the "front" of the head gasket that protrudes out of the front of the block/head mating surface (at least the two I have put together did :-\) This tab is non existent on the rear of the head.
On most big blocks (Chevy, Ford, Olds, MOPAR) you need to have at least 10# of pressure at speed to stave off air bubbles....Which lead to steam pockets. If the pump is worn out or damaged, it will be difficult to make that pressure.
Hope this helps.
Good luck!
GT
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Is there a way to check the pressure from the jet ???