78 marnier 150 starting and idle probs

[bluebear57]

i have an 87 marnier that starts cold pretty good but takes a long time before it will idle in gear if you get right on it it runs great but when you stop for a while its starts and dies unless you through it into gear or it will kick out the starter and when it idles it idles at 1100 rpms ive tried everething any suggestions

 

[j_martin]

Re: 78 marnier 150 starting and idle probs

It only idles at a high speed. Start your diagnostics with a compression check.

 

[SparkieBoat]

Re: 78 marnier 150 starting and idle probs

sounds like your low speed passage/s are clooged..carbs need good cleaning. also a new set of correct spark plugs..check compression and spark as Martin mentioned.

 

[bluebear57]

Re: 78 marnier 150 starting and idle probs

thank you for your reply compression is where it should be inot sure which plug is best for the 150 mag changing plugs seems to help for a little while sometimes especcially the starting ill use my manual to find out more about low speed passages thank you very much for your response

 

[bluebear57]

Re: 78 marnier 150 starting and idle probs

not sure if my respomse went through but thanks again compression is fine and new plugs seem to help for a little while not sure which ones to use for the 150 mag thanks again for your time

 

[carholme]

Re: 78 marnier 150 starting and idle probs

bluebear;

Your post title says '78 Mariner but in your posts you say it is an '87 Mariner.

Does your s/n lie in this range?

150 B169771 - B241880 1987

As I don't see a 150 pre 1979, I will presume that yours is a 1987 and if so, here is the parts list and you can look under:

FLYWHEEL, STARTER MOTOR AND IGNITION COILS
for your plugs.

http://www.crowleymarine.com/mercury-outboard/299.cfm

If this is not correct, can you provide the engine s/n?

Gerry

 

[Superjetjim]

Re: 78 marnier 150 starting and idle probs

Pull and clean your carbs, you'll need an old tooth brush and some carb cleaner to clean out the tiny passages, only a couple hours work if you take your time. If this doesn't sort it you need a fuel pump overhaul kit - the diaphram wears out and doesn't seem to pulse enough Gas at low throttle settings.

I did both of the above on mine and it went from 1,000RPM ropey idle to 850RPM purring with perfect hole shot.

Cheers,

Jim

 

[bluebear57]

Re: 78 marnier 150 starting and idle probs

thank you for your help