90 HP Force hard to start warm

[medwest]

This engine has recently had fuel lines and primer bulb replaced. Carbs were adjusted and timing set. Now engine starts good when cold but hard to start warm. Needs choke and fast idle to start which is different for this engine. Then to keep it running I have to slam it into gear and let it run bogged down like it wants to stop for maybe a minute, then it takes off and does great. I can start if after stoping unless it sets for 10 min and then the same problem again. Fresh gas and new (but different plugs). Can't see any more gas leaks. Thanks. RGB

 

[roscoe]

Re: 90 HP Force hard to start warm

Typical symtoms of a fuelpump, leaking into the block, causing a flooded condition. The fuelpump diaphram is likely shot.<br /><br />Easy to rebuild with a kit from Mercury dealer. $8 or $14, depending on which pump you have, the square pump, or the oval pump with 2 round humps.<br /><br />Let us know if it fixes it for you.

 

[medwest]

Re: 90 HP Force hard to start warm

Can I do this repair myself with the kit? I haven't had to do any major work on this engine myself. Any tricks I need to know to stay out of trouble? It does make sense that it feels flooded when trying to start warm. RGB

 

[springhead]

Re: 90 HP Force hard to start warm

All you will need is a flathead screwdriver,<br />The kit is a diaphram and a gasket. simple to rebuild like Roscoe said.<br />If you have the money buy 2, i used to rebuild my 90 force fuel pump every season.

 

[roscoe]

Re: 90 HP Force hard to start warm

Here is a diagram of your pump.<br />Just replace the old parts with the new.

 

[medwest]

Re: 90 HP Force hard to start warm

I appreciate the help. I got the gasket and diaphram. The old diaphram was stretched but appeared not to have any defects or holes. To the best of my knowledge it was original to the motor. Can you tell if they are bad by looking? I have not had a chance to test the boat yet to tell if this has solved the problem. Thanks Roscoe and Springhead.