Mercuiser 3.0 (181) 1987 starting issue

jdejongh

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Well got towed into the marina this weekend..... I have a 1987 Four winns hoizon 190 with mercruiser 3.0 engine. Has run great for me all season. This weekend we were out boating all day and we decided to stop for a swim. When i turned off the ignition key the engine sputtered a couple times before shutting down.... When we were done with the swim, i went to restart and it would crank over fine, but not fire up. After several attempts of starting (10 minutes) the battery finally got tired and i had to call for help. A similar situation of sputtering before shutdown and immediately followed by hard to restart has happened before , but i was eventually able to get it restarted that time. Any help would be appreciated!!;)
 

Kainon

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Re: Mercuiser 3.0 (181) 1987 starting issue

Fresh fuel ? ( like no OLD Fuel from last year in the tank untreated ? ) Sounds like your carb needs to be adjusted if not cleaned and rebuilt.

DO you have a fuel/water separating filter before the fuel pump ?

When was it last checked or changed ? Dump it into a glass or clear plastic container and let sit for an hour, see if you see bubbles (water) on the bottom.
 

Kainon

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Re: Mercuiser 3.0 (181) 1987 starting issue

Could also be the carb needs a simple adjustment. the idle mixture screw ( not the throttle stop ) under neat the front or port side of the carb, it should be adjusted with the engine warmed up and idleing in gear in the water. ( can be still tied to a trailer or the dock, i find a little better than underway. )
 

jdejongh

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Re: Mercuiser 3.0 (181) 1987 starting issue

i did fail to mention that in gear im idleing at about 140 rpm.. if i take it out of gear and put it in to nuetral im sometimes idle at 2200 rpm... i see in my engine manual that i should only idle at 800 rpm or so. The fuel is fresh .have filled up several times this season.. thanks much for your replies. so if i understand you correctly, i should set my idle with boat in gear and adjust (idle screw).
 

Kainon

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Re: Mercuiser 3.0 (181) 1987 starting issue

I'm sorry, I seriously doubt you are idleing at 140 ( maybe a typo ) I like 600-650 in gear, 800 in neutral over 1000 in neutral and you'll damage your outdrive when shifting.

Do a little searching here you'll find many post on how to properly set the idle mixture and idle stop. ( on the side lever on the carb. Sometimes the throttle cable at the carb needs to be removed to set and or adjusted too.

In gear, in the water, not just on a hose sitting in your driveway ( not the best but can be done)

There are 3 adjustments, the throttle cable, the idle stop on the arm of the carb, and the idle mixture (brass) under the front of the carb.

DO NOT tighten the brass one, you will damage it and the seat it goes into.

GENTLY turn it in till it stops ( counting the turns ) then back out 1.25-1.5 turns (typically) if your more or less than that you could have carb or gasket issues. Also if you dont have the proper gasket under that Carb this can cause IDLE Issues..
 

jdejongh

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Re: Mercuiser 3.0 (181) 1987 starting issue

yes it was a typo, my idol is at 1400 rpm.. thnak you for the suggestion i will adjust that idle
 

jdejongh

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Re: Mercuiser 3.0 (181) 1987 starting issue

just to clarify im to adjust the idle stop not the idle mixture ..correct??
 

Kainon

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Re: Mercuiser 3.0 (181) 1987 starting issue

no problem, please read what I wrote as I think I explained you have to check 3 settings..

first, disconnect the throttle cable from the carb, this will tell you if you need to touch the carb at all....

a HIGH idle as you mentioned will cause it to do what you mentioned when shutting it off and will also cause it to be hard-starting.
 

Kainon

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Re: Mercuiser 3.0 (181) 1987 starting issue

I also recommend you take a picture of the carb and post it, as I mentioned if you have the wrong gasket under the carb it will cause other problems.
 

Kainon

Chief Petty Officer
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Re: Mercuiser 3.0 (181) 1987 starting issue

no problem, glad to help.

Adjusting the idle mixture ( not the idle stop ) takes a little time and patience and a little hearing, search the posts hear for "adjusting Idle Mixture"
 

jdejongh

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Re: Mercuiser 3.0 (181) 1987 starting issue

Thanks for the help. The idle adjustment seems to take care of the issue. I did notice though that the electric choke thermostat doesnt seem to operate as should.... (doesnt close on cold start, so i will find that part and get it replaced..thank you again!!
 
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