hard start

duane.mosley

i have a 2006 250 ec with the volvo penta 5.7 EFI. the boat starts great when it's cold, bump the key and it fires right up and runs and idles  great.  this weekend i noticed that after cruising for a bit and shutting it down. i would have to work the throttle a little bit for it to start. it wasn't anything drastic where i had to keep pumping the throttle, but i would have to pump once or twice as if it was a carbed engine. once started, it ran just fine. the motor got a fresh tune up 3 weeks ago, fuel filter, oil, filter, plugs, wires, cap and button, thermostat, temp sending unit. the temp has been verified with an infrared thermometer and is not over heating. any and all assistance appreciated and thanks in advance.

bazza

Same happened to my 5.7 300hp gas volvo penta on 2010 280, possible cause could be not using the engine bay vent fan and not enough oxygen for good mixure.
Barrie

duane.mosley

i always use the blower upon starting as well as at idle speed. i'm going to take my fuel pressure gauge with me this weekend to check pressure during the hard start. it starts fine when coming off the trailer or sitting over night. it seems to only happen when we cruise for an hour or so and sit for a few.

Michael T

Possibly vapor lock? I don't believe V.P. has a cool fuel module like Mercury to cool the gas pre entry into the fuel rails.?

MajorAppeal

Was this every resolved?  I am having the same issue.  Cold start and it starts right up.  Anytime engine is warm, I need to give it throttle to get it started.

russellh

Mine does just the same. It's common so I'm told. Hot start problem. It's likely a temp sensor. Engine thinks it's still cold so dumps in as if it's being cold started but as it's already got enough fuel as it's warmed up it slightly floods it. That's leymans speak. Like you say a tiny bit of throttle on start up and it's fine. I'll get round to changing the sensor soon but I believe there are two? Others on here will say which one it is im sure. An easy fix though

laureniac1

2005 270 same problem when restarting after warmed up. I was told when restarting tune key half way and wait a few seconds before starting. Can't remember if that helped it's been a winter and have not started it yet this year

[Deleted User]

I have the same issue with my 5.0 VP. From reading other owner's comments, I've learned the following that never fails to get the motor running.

Turn the key to the first detent. After the last beep, count for ten seconds, then turn the key to the start position. The engine should fire right up. If that fails, press the center button on the shift lever to allow throttle only, apply full throttle and crank the engine for as long as it takes for the engine to start, typically up to 5 seconds, then immediately return the shifter to neutral.

Andy

russellh

I'll give the key turn a go but I'd never put full throttle on to clear it as it would flood for sure. I have to put in neutral and then just a tiny bit of throttle and she starts

MajorAppeal

I checked the resistance on my temperature sensor today and it is changing significantly as the temperature changes.  I don't have the specs for it to know if the resistance is in line with what it should be so I am ordering another one on amazon for $14.  I'll change it out and let you all know the outcome.

russellh

Thanks major can you send me the link on amazon please. Good luck 

[Deleted User]

I believe the WOT throttle hot engine restart procedure is described in the VP engine manual. It is done to overcome an overly rich mixture, what many people called "flooding" on carb equipped engines. It does not cause the problem, it overcomes it. This won't happen that often to my boat, but when it does I'm usually a couple of miles off shore in the open ocean, and I've always got her started using one or the other of the two techniques I described.

Andy

[Deleted User]

Here is the starting info from the VP manual.
Andy

duane.mosley

i replaced the temp sensor last year and it did not resolve the issue. the engine has since been rebuilt  and have not had it out this year to know if it's still doing the hard start issue. i would open the throttle wide open but as i turned the key, i was pulling back the throttle not allowing it to start at WOT. worked for me every time so it is definitely a fuel over flow issue, soon as it has plenty of air, it fires right up.

rinker270nb

I had the same problem with a brand new motor.  I changed the cap and wires and it fixed it for a few months. I learned that the key needs to be at first dent for about 10 seconds and that data needs to be collected for a sure fire. Lack of battery load was an issue I didn't know I had at the time as well.  Good luck, I am watching this thread to see what the final fix would be. (IAC was another suggestion but it was brand new.  Screwy?!)

duane.mosley

i did replace the IAC valve during my rebuild so i will update once i have it running. just waiting on the time to pick up my oil, oil filter, anit freeze, and power steering fluid, and  i will be ready to fire it up.