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Slow start especially when warm
https://www.smwebhead.com/phpBB3/viewtopic.php?f=11&t=14337		 Page 1 of 1
Author:  schoolsOut [ Fri Jul 31, 2015 8:03 am ]
Post subject:  Slow start especially when warm
So I'm giving the boat a good workout at smith mountain lake this weekend and I have been noticing that it starts slow when it is warmed up. Like when I stop to switch skiers/boarders/tubers. Sometimes I have to hold the key over fairly long to get it to fire up. If I don't hold it over long enough then when I try to start it again, it is even harder to start. A couple of times I had to give it gas to get it to fire. Any thoughts? Time for a tune-up?
Author:  Rick2752 [ Fri Jul 31, 2015 8:17 am ]
Post subject:  Re: Slow start especially when warm
Just a thought....try turning the key for a couple seconds on then off. Do that a few times then try to start. When you turn key on it primes the fuel pump. Could be a fuel filter issue, could be a pump issue.
Author:  schoolsOut [ Sat Aug 01, 2015 8:29 pm ]
Post subject:  Re: Slow start especially when warm
Rick2752 wrote:
Just a thought....try turning the key for a couple seconds on then off. Do that a few times then try to start. When you turn key on it primes the fuel pump. Could be a fuel filter issue, could be a pump issue.


Good thought. No change, however. Another symptom is that when starting it cold, it fires up then the rpm's drop and it either shuts off or almost shuts off. It if does shut off, I have to either crank it for longer than usual or even give it gas while cranking.
Author:  Rick2752 [ Sun Aug 02, 2015 7:55 pm ]
Post subject:  Re: Slow start especially when warm
I would google symptoms of a bad low pressure fuel pump for your motor. Lots of other things to change first as the pump I expensive.
Author:  schoolsOut [ Mon Aug 03, 2015 7:55 pm ]
Post subject:  Re: Slow start especially when warm
Rick2752 wrote:
I would google symptoms of a bad low pressure fuel pump for your motor. Lots of other things to change first as the pump I expensive.


Trying not to sound like an idiot, but is the low pressure fuel pump the one in the tank? Then there is a second high pressure fuel pump on the engine? If the fuel pump was the culprit wouldn't I lose fuel when running at WOT or when accelerating hard? It does not cut out at all, just starts hard at times (flooded?) and shuts off right after starting at times.

As a first step, tonight I cleaned the throttle body to see if that makes a difference. I was thinking about buying a code reader to see if the ECM is throwing any codes but after thinking about it, any codes would be cleared out when I turn off the battery so I am not sure if that is worth it yet. I'm heading to the lake for a few days later this week and I should be able to see if the throttle body was the problem. It didn't look terribly dirty. Here are two before photos and an after:

Before:
Image
Image

After:
Image
Author:  Technologic80 [ Mon Aug 03, 2015 9:33 pm ]
Post subject:  Re: Slow start especially when warm
I gotta say, as being familiar with replacing ALL the fuel pumps on my twin Volvo Penta Four Winns boat... your problem sounds JUST like mine and a lot of others when 1 (or both) of the pumps starts to go bad. And its not a matter of IF they will go bad, its certainly WHEN.

You can try removing the fuel pumps and checking the inlet screens for debris. Whens the last time you changed the water separator/fuel filters?

But really... all that aside, it definitely sounds like fuel pump drama and that you will be replacing 1 or both in the very near future.

OH I just remembered - when mine would act up, I could have a helper tap the fuel pump with the handle of a screwdriver kind of hard while I cranked the engine, and the engine would start right up. This method may or may not work for you, but it helped me.
Author:  schoolsOut [ Mon Aug 03, 2015 10:42 pm ]
Post subject:  Re: Slow start especially when warm
Technologic80 wrote:
I gotta say, as being familiar with replacing ALL the fuel pumps on my twin Volvo Penta Four Winns boat... your problem sounds JUST like mine and a lot of others when 1 (or both) of the pumps starts to go bad. And its not a matter of IF they will go bad, its certainly WHEN.

You can try removing the fuel pumps and checking the inlet screens for debris. Whens the last time you changed the water separator/fuel filters?

But really... all that aside, it definitely sounds like fuel pump drama and that you will be replacing 1 or both in the very near future.

OH I just remembered - when mine would act up, I could have a helper tap the fuel pump with the handle of a screwdriver kind of hard while I cranked the engine, and the engine would start right up. This method may or may not work for you, but it helped me.


Well, that does not sound encouraging. Am I going to get stranded on the lake in the near future, in your estimation?
Author:  Rick2752 [ Tue Aug 04, 2015 7:07 am ]
Post subject:  Re: Slow start especially when warm
I doubt it but would make sure tow insurance is up to date. Anyway, your fuel pump is on the front left side if the motor when facing back of boat. Read my thread 5.7 bogging down. I took it apart and there's lots of pics. Is there any whine from the pumps? Put your hand on each one. Is one hotter than the other? If you are facing back of boat pump is on the left and low pressure is left side pump. Have you checked your distributor cap? Look for cracks.
Author:  schoolsOut [ Tue Aug 04, 2015 8:11 am ]
Post subject:  Re: Slow start especially when warm
Rick2752 wrote:
I doubt it but would make sure tow insurance is up to date. Anyway, your fuel pump is on the front left side if the motor when facing back of boat. Read my thread 5.7 bogging down. I took it apart and there's lots of pics. Is there any whine from the pumps? Put your hand on each one. Is one hotter than the other? If you are facing back of boat pump is on the left and low pressure is left side pump. Have you checked your distributor cap? Look for cracks.


So, I am learning (slowly), but just to clarify...here is a look at a fuel pump assembly. It consists of two fuel pumps, a high pressure pump (on the right here) and a low pressure pump (beside it to the left).

Image

From what I have seen, I can replace each pump for about $200 or the whole assembly for $700+. I will take IR temp readings on the pumps to see if one is heating up. I will also take a look at the distributor cap. I assume plugs and wires are all original. I plan to change them all in the off-season. Maybe the cap should be replaced then too.
Author:  Rick2752 [ Sat Aug 08, 2015 6:31 am ]
Post subject:  Re: Slow start especially when warm
I think I would start with the distributor cap and wires. You could also by an inline spark tester for your plug and see if spark looks the same when its warm. I could be wrong but im not sure you can buy the low pressure side. You are correct on the pump info.
Author:  schoolsOut [ Sat Aug 08, 2015 7:52 am ]
Post subject:  Re: Slow start especially when warm
Just a quick update. We had the boat out for most of the day Wednesday and Thursday. Started and stayed running perfectly all day, both days. Seems the throttle body cleaning did the trick. I will still be giving a tune-up this fall. Thanks for all the help. I learned some valuable fuel pump information and will be prepared to deal with those issues when they arise.
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