Hard to start

[lana-n-me]

1979 150 h.p. S#5342163
I had a mechanic tell me he did not know what was wrong since he did a complete test including checking spark, compression and fuel pressure. The only thing he would say is he would start with a carb rebuild.
Problem is it will not start easily, consistently. Some days it will start on muffs but fail when I immediately put it in the water. Other days it will not start until the following day when it fires immediately with little cranking.
The only consistent factor seems to be a fully charged battery. Maybe because on it's stubborn days it needs to crank a lot before it fires. I have all brand new fuel lines, primer ball and fuel pump has been rebuilt.
Problem seems to be just in starting because it runs great once it is running. It is just very difficult to start.

 

[CharlieB]

Re: Hard to start

In-line 6?

They like a LOT of fuel to start, seem to be the coldest blooded beast on the water. But once running, well, there ain't anything like it.

Ensure the carbs are PERFECT. Clean, float height, synch.

Idle mixture set to fastest/best idle while in Forward gear while ON-THE-WATER, PLUS another 1/8 turn, slam the control to WOT. If even the slightest hint of hesitation, bog, or lean cough, open the idle mixture screws another screwdriver blade width and retest. Repeat until perfect.

Cold starts, choke like you are trying to flood it, until it starts, then immediately release the choke, but be ready to just bump it again when the fast idle RPM starts to fall off. Repeat as needed until fast idle speed remains steady and you can back idle speed to normal idle.

Then enjoy your ride.

 

[timmathis]

Re: Hard to start

Try giving the bulb 2 or 3 extra slow long hard pumps before starting. Works for me with my 75 150 hp. When cold they can be hard to start. Never use starting fluid that will kill it quick. I have seen some people use pre mix in a spray bottle. Also make sure the motor is all the way back gas runs down hill. Hope I help. Good luck,Tim

 

[Chris1956]

Re: Hard to start

The 1978 and newer 150HP motors are V6. These motors should have fuel enricheners instead of choke plates. Make sure the enrichener works. There may be a manual button on the enrichener solenoid. Try operating that while cranking and see if it starts better.