2001 DF90 Cold Starting Issue

[buhrly]

Ok, so I have the 90 horse that I got with a boat purchase. The motor does not like to start in the cold. Well, at least stay started. When it is cold (I live in Alaska) it is a heck of a time to get it running and away from the dock. Granted it’s cold outside. The air temperature is 20 degrees and the water is 38 but its efi right. So at the dock for the first start of the day it will take 15-25 times of starting it to get it to continue to run. It turns over, starts and runs for a few seconds and dies. Not a sputter die but like someone turned it off. After many tries of this same process it will stay running. Once warm it runs well and will start no problem on the first try for the rest of the day.
It went to the shop and got valves adjusted, plugs, fuel filters and water pump. Those didnt fix it...

[Handsomerob1980]

What is the compression on the engine cold? A few things come to mind but I would check compression first. Also what is the operating temperature of the engine, 20 is about -7C so that is quite cool. The Fuel map may not be setup to operate in that temperature it may only be able to enrichen the fuel mixture down to a certain temp. If it is an acceptable temp for the engine operation there may be an issue with a skewed temp sensor, either air temp or engine temp. Have you added gas line antifreeze? there could be small amounts of ice in the fuel, do you have a water separator in the boat? Condensation can cause water in fuel issues with widely fluctuating temperatures. Just some ideas.

[buhrly]

Hi Handsomerob, The compression is good. I think they said 120 at each. There is a water separator but I haven’t been using a treatment on the fuel. That would be easy to try. The fuel mapping is a good idea. It was said to start right up in warmer temperatures without issue. The mechanics said they couldn’t duplicate the issue with it in the shop but i’m not sure how long they run it or if they just heard it start.

[Murray]

If the mechanic had no issues starting it in the shop(after engine had warmed up a bit) and it starts fine once warmed up then I agree that some gas line antifreeze would be a good start. I’m hoping some of the senior members chine in with their thoughts re the ECM and cold temperatures. One would think that it should start in cold weather assuming your fuel is fresh and no moisture in the system.

[redlowrey]

Providing the iac valve is functioning properly check the signal voltage on the temp sensor with the key on engine cold, in that sought of temp it should be nearly 4 volts, inlet air temp around 3 volts. If the temp sensor voltage is under 3 volts the computer will not inject enough cold start fuel.

There will be other things to check but start there.

[buhrly]

This is some good info! It is back at the shop and they were wanting to change the ignition key. It definitely seems that the voltage should be checked also.

[Murray]

Bare in mind that the voltage reading will be different in a warm shop than sub freezing temperatures.