1990 mercury Black Max 150 hard start

[lawrencebarnes]

Hello,

I have a 1990 merc 150. When I purchased it, it ran fine on land. I took it to shop had water pump and spark plugs changed. 2 weeks ago I hooked it up to ear muffs and started with no problem. I took it out on the bay today for the first time. Before launching it I tried a test crank It would not turn over at all, I figured that I may have flooded the carbs so I let it sit for about 20 mins then finally got it to turn over.

I then launched the boat, as soon as I get it in the water same problem, will not crank. After several attempts I finally get it to crank. Then I put it into gear it takes off and dies out after 5 seconds and it would not start again at all. Luckily I was close to the launch and able to paddle back in. Any help would be greatly appreciated!

Thank you!

 

[racerone]

To the untrained ear they all start and sound great on dry land.----Start with a compression test.----Then see if you have spark on all 6 leads.-----Might be as simple as opening the low speed idle mixture screws.

 

[lawrencebarnes]

Ok thanks, I will try to adjust the mixture screws. I just had spark plugs changed and compression test done. I did notice that there is oil on the spark plugs when I looked at them today. Is that normal?

 

[racerone]

No, no -----You need to check and see if you have spark on all leads.---These motors will run quite nicely on 5 cylinders.

 

[lawrencebarnes]

Forgive me if this sounds like a crazy question. But when you say leads are you referring to the spark plugs?