'01 70 HP Johnson-will not start hot

[Tommy H]

Hello, I have a 2001 70 HP johnson. This engine starts very wll when it is cold. It will run for hours, as long as i don't turn it off. I have had it out all day running at cruising speed, trolling, and idling, but the first time you turn it off it will not restart until it has about 30 min. to 1 hour to cool off. When attempting a hot start it spits and sputters and backfires but will not start. It seems to me that it is a carb-choke issue but i am unsure. Any suggestions would be greatly appreciated.

 

[tashasdaddy]

Re: '01 70 HP Johnson-will not start hot

welcome to iboats. what are you starting procedures when you go to start it. exactly. let's see if it's the motor, or operator error. usually the last. how long have you had it, and what has been done to it to service it.

 

[Tommy H]

Re: '01 70 HP Johnson-will not start hot

Thanks for the reply. As to your questions, I have owned this engine since it was new. The hot start issue has never been a problem until the last few times I had it out. Once last fall and twice this year. No change in starting procedure. I change the plugs and lower unit oil each year, and water pump impellor every other year. Thats about it as far as service. I did change fuel line and bulb this year with no change in starting habits. Any further suggestions would be appreciated.

 

[tashasdaddy]

Re: '01 70 HP Johnson-will not start hot

i don't have the test procedures, for your motor, but you need to test the coils, and powerpack. when it is doing this.

 

[Tommy H]

Re: '01 70 HP Johnson-will not start hot

Just a little bump to get some more attention for this problem. I posted this problem on another board and 2 or 3 other people had the same problem, but no one seemed to know the fix. If anyone has had this problem before please advise as to what I am up against. If not anyone have any ideas as to what it would cost to have a proffesional diagnose the problem?

 

[offshore100]

Re: '01 70 HP Johnson-will not start hot

Don't think it's electrical, because that usually gets worse as the engine heats up. I think it's fuel related too....vapor lock? "Spitting, backfiring" could be indicators of lean condition?
Try cracking your carb bowl drain plugs before restart and make sure fuel is coming out of them whilst squeezing your priming bulb. Just a thought.

 

[reload]

Re: '01 70 HP Johnson-will not start hot

I tend to agree with os100, some sort of fuel problem. You did not reroute the fuel ines did you? Vapor lock seems reasonable.

 

[Tommy H]

Re: '01 70 HP Johnson-will not start hot

Thanks for the suggestions. But I am not sure what a vapor lock is or what causes it. What are some things to do to prevent this from happening again?

 

[Texasmark]

Re: '01 70 HP Johnson-will not start hot

Divide and conquer since you seem to have equal answers in the ign and fuel arenas.

Get a spray can of Deep Creep (auto parts store), remove anything in the way of you looking directly into your carbs. Turn it off and before you try to start it, spray some into the carb intakes. If it lights off fuel is your problem. If you get no reaction, ignition.

Most of my hot no-start problems have been ignition coil related...never had a vapor lock problem and I had a '75 70 hp.....problem I had with it was a stuck closed tstat....before the days of the warning buzzer. Course todays fuels may be more prone to vaporlock.

Mark