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Thread: Hot start problems with 5.7 GM marine power

  1. #1
    Member ocnfish's Avatar
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    Question Hot start problems with 5.7 GM marine power

    Yesterday, I drove all the way to Cape Clear, Montague from Seward. After catching a 60" halibut I decided to head back but the engine would not start. Fortunately my honda 9.9 kicker started me back to port at about 5.5 mph. I also used the 6 amp charger to recharge the two starting and one houde battery. After 3 hours of cooling and getting the volt indicator over 12, I managed to restart the 5.7 GM and the rest was a great ride. I am thinking that the batterys are a littel older, about 5 years and if I leave the sounder on along with the water pump along with the sterio for about two hours, it is too much for the old batterys.

    Or could there be some kind of vapor lock going on?

    Any thoughts are welcome, it is a little scarry trying to cross Blying sound at 5 mph using the kicker.

  2. #2

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    Did the engine crank normally, and then not start? Or, did it crank slowly?

  3. #3
    Member ocnfish's Avatar
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    Default Hot start

    I would have to say that it did, I actually tried about three times to start and when I noticed that the starter was slowing down I stopped cranking. The diference the last time was I let volts charge to above twelve. When I cleaned the salt off the boat after the trip, I hooked up the garden hose and muff and the engine started immediately. Just hot starts in the marine environment. If it were a fuel filter problem it would start hard every time. It is an injected engine, the 280 hp Volvo Penta version.

  4. #4

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    Get new batteries - you need them anyway as you pointed out. Old batteries can and do make things do some really strange things. I bet with fresh batteries that your problem goes away.

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    Member Dupont Spinner's Avatar
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    Default

    Pret near impossible to have a vapor locked injected motor. I would lean more towards batteries to start. Have them load tested before replacing. Also get a pressure reading for your injection system if batteries come back ok. You may have a high pressure pump failing. I had one that was hard start and then would only allow the boat to idle on a warm engine.

  6. #6

    Default Voltage

    If your starting battery is at or below 12, volts your battery is dead. It wont start a motor with a heavy amp load. It isn't going to have enough reserve amperage to crank. It will however operate your electronics until it reaches around 11.6 volts or their low voltage thresehold.
    A charged battery has 12.6 volts, at 12.2 volts it's half discharged. At 12 volts it's nearly 100% discharged. A lot of EFI motors won't inject once the battery drops below 11.9 volts. So even if the motor is running and the battery starts going down when the low voltage level is reached it will die.
    Boat batteries should be replaced about every 2 years as a preventive maintenance.
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    Member ocnfish's Avatar
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    Red face Hot start problems

    Boat mechanic said bring it in, this engine typically has problems with the fuel pump when it gets hot ... Just to be sure I am going to get two new 24 starting and one 31 house battery. Any opinions on on glass mat vs traditional? Glass matt cost more but is it worth it?

    Thanks one and all ....

  8. #8

    Default Battery placement

    Quote Originally Posted by ocnfish View Post
    Boat mechanic said bring it in, this engine typically has problems with the fuel pump when it gets hot ... Just to be sure I am going to get two new 24 starting and one 31 house battery. Any opinions on on glass mat vs traditional? Glass matt cost more but is it worth it?

    Thanks one and all ....
    Not sure where your batteries are located in your boat.BUT, If you have enough room choose the Group 27 series over the the 24. The 27 has 15-20% more storage capacity than the 24. Lead acid batteries store more amperage per size than AGM batteries, and are less expensive. AGM batteries are preferred if the battery storage is in a cabin however since they don't gas, and are maintenance free (pretty much), AGM batteries also have a lower storage/shelf voltage loss.
    All batteries discharge in storage, lead-acid batteries at about 4% per month. AGM style batteries at a lesser rate depending on style and manufacturer.
    " Americans will never need the 2nd Amendment, until the government tries to take it away."

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    Member Dupont Spinner's Avatar
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    Default

    On another note on Glass Mat Batteries....they have a different charger then regular lead acid batteries. Also put in the biggest battery you can.

    Most newer motorcycles have gone to a glass mat battery....they are nice except for the price.

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    Member ocnfish's Avatar
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    Default Battery choice

    The boat is a 2003 Ospery 26 long cabin, both starting batterys are in the storage boxes on the step up to the rail walk way around the cabin. I will get out the tape measure and see if I can squeese the 27's in. Haven't skimped on anything so far with this boat. Battery set up was AMDS choice, better to upgrade if possible. I think I will go with lead acid as no batteries are in the cabin.

    Looking back, the coolest thing was the honda 9.9 kicker 6 amp charger putting enough kick back into the battery system to get a restart. That kind of redundancy amounts to saftey options that are essential out on big water.

  11. #11

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    Keep us posted on this. I am not buying the fuel pump diagnosis just yet. The reason that I say that is the boat runs just fine warm and has plenty of power when warm, right? Well, that tells me the fuel pump is very happy. But, once again, let us know what you find.

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    Member ocnfish's Avatar
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    Default Hot start problems with 5.7 GM marine power

    I will let you know, I am taking this post with me and sharing it with Jeff. As far as full power goes, from Cape Reseruction all the way back to Seward we were showing 4300 RPM and had a peak water speed of 44 mph after I got the trim right. Wasted a lot of gas but it was fun.

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    Member akriverrat's Avatar
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    Default 2 fuel pumps

    with my 5.7 litre marinepower i have two fuel pumps. one is a pickup pump to get the fuel from the tank to the main pump. my buddy has a 5.7 ;itre marinepower that he had some problems with vaporlock and installed some clamshells on the doghouse for vetilation. hasnt had a problem since. not saying thats your problem jsut what i have experianced. i have not had any problems with heat on my boat but have thought about installing clamshells on the tops of my gunnels and routing cool air to my motor while underway.

  14. #14
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    Default Hot start problems with 5.7 GM

    If you want to check out your EFI engine, I have a Diacom PC based engine diagnostic system posted on Craigslist (see http://anchorage.craigslist.org/boa/698597429.html). It runs full diagnostics on your engine, not just the error codes. You can buy this unit for what it will cost you to have your engine checked out by a marine mechanic. Great tool for the boater who wants to do their own engine work. Call me at 441-6721 if interested as I'm in Seward the next few days.

    I have a diesel now so no longer have a use for it.

    Good luck and good fishing!

  15. #15
    Member ocnfish's Avatar
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    Default Hot start problems and what the mechanic found

    According to Jeff, I had a newer style fuel pump and hot or cold we had 60 PSI fuel presure. Load test on all three batteries and they were good.

    When he finally got it to not hot start (had to go through several cycles) the coil did not give a normal reading. The coil was mounted on the engine and was quite hot to the touch. By the way his computer code check said the engine was perfect, no bad codes.

    We are going to put a new coil and I am going to spend half a day running around in circles stopping now and then to be sure that we corrected the problem.

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    Default

    Quote Originally Posted by ocnfish View Post
    Yesterday, I drove all the way to Cape Clear, Montague from Seward. After catching a 60" halibut I decided to head back but the engine would not start. Fortunately my honda 9.9 kicker started me back to port at about 5.5 mph. I also used the 6 amp charger to recharge the two starting and one houde battery. After 3 hours of cooling and getting the volt indicator over 12, I managed to restart the 5.7 GM and the rest was a great ride. I am thinking that the batterys are a littel older, about 5 years and if I leave the sounder on along with the water pump along with the sterio for about two hours, it is too much for the old batterys.
    Your original symptoms sure led us on a merry chase. Having a bad coil does not explain the low battery voltage. I have a load tester and there have been several times it told me a bad battery was good and having 5 year old batteries on a boat is not good unless they are very high quality batteries. There is also the question how good is my battery tester compared to Jeff, I am sure his is a lot better.

    To be on the safe side think about replacing one battery and/or carrying a set of jumper cables if you have them.

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    Default Code Reader vs. Diacom Plus

    Quote Originally Posted by ocnfish View Post
    According to Jeff, I had a newer style fuel pump and hot or cold we had 60 PSI fuel presure. Load test on all three batteries and they were good.

    When he finally got it to not hot start (had to go through several cycles) the coil did not give a normal reading. The coil was mounted on the engine and was quite hot to the touch. By the way his computer code check said the engine was perfect, no bad codes.

    We are going to put a new coil and I am going to spend half a day running around in circles stopping now and then to be sure that we corrected the problem.
    Ocnfish - the code checkers are primative $40 gadgets that only tell you if a code is set, no comparison to the Diacom PC based unit I have. Plug this baby in and you get everything going on with your engine. It will record 10 minutes of operating conditions under all load conditions for you to diagnose problems too. It's an expensive tool but nothing better available to tell what's up with your engine.

    Hope the coil is your answer. They're pretty cheap.

  18. #18
    Member ocnfish's Avatar
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    Default Hot start problems

    I will find out this weekend, heading out of Seward for Cape Clear. At about Cape Resrecturion and Barrwell Is. I will shut everything down wait a few minutes and try a couple of hot starts. I have confidence in my mechanic and I know when I am getting in over my head, I do maintenance on a lot of the little stuff myself. For this problem though I think it was time to call in the expert. We will see ....

  19. #19
    Member ocnfish's Avatar
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    Default the final chapter with hot start problems

    I know this is an old post but there are a lot of GM 5.7 marine power motors out there.

    The last two years I have used the big engine for trolling because the OMC motor mount for the 9.9 honda kept the motor too close to the back of the boat to use the throttle hold, too steep angle.

    The excessive idling of the big engine had a real bad effect on the valves. Acording to Jeff Miller most of the valves were "tuliped" even a couple of the valve seats needed to be replaced. The compression check ranged from 65 psi to 140 psi, good readings would have been 150 psi for all cylinders.

    Well ... I now have a main engine with good compression and because the OMC mount broke last year and it was replaced with the biggest Gerlach 4 stroke mount made I think I will be good to go now.

    Very expensive lesson to learn and it was not helped by a not so professional boat repair shop in town that set me back two weeks charged me $546.00 for a compression test. They also told me that I needed a new motor and that they would not do the replacement. Jeff did an additional differential compression test and determined that the leak was through the manafolds ... bad valves.

    Oh well

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