Force 70hp outboard, starts, runs, but trouble restarting after sitting

[Force39]

Hi, My 70 hp Force starts fairly easy, but after running and sitting a while it has trouble restarting. Some times it won't restart and I get towed to my dock. Next day it starts fine. Also, the fuel pump bulb does not firm up, but has been that way for a couple seasons. When I unclick the fuel line connector it will pump up firm to the input side of the connector. Things I have done: replaced all fuel lines,fuel filter and bulb. Took fuel pump apart, appeared fine, no tears. Pulled fuel line out of tank. It had a little screen in the inside bottom of tube. It was clean. Put in new spark plugs. Added 10 oz.of Sea Foam to gas tank. Let it sit and then ran motor for quite a while. Used carb cleaner in carburetor. Added Stabil to fresh 5 gallons of gas and ran for some time. Any thoughts on this appreciated. Thanks!

 

[roscoe]

I think you were on the right track with he fuel pump.
Very common to these to go bad.
A rebuild kit from a Merc dealer is under $25.
Replace the gaskets, diaphragms, and check valves.

What happens when these go bad, is they leak fuel into the crankcase while you are sitting there fishing or tanning or whatever.
This causes a flooded condition on one cylinder.

Next time it happens, you could remove the sparkplugs and inspect / compare them.
Bet you will find one or more are very wet.

Keep us updated, it will help future members with the same issue.

 

[Jiggz]

You seem to have done just about everything. Do you have a clear fuel filter installed between the fuel pump outlet and the carb inlet? This is more for troubleshooting than fuel filtering.

 

[Force39]

The fue pump 'looked' good, but it is original. I will get the rebuild kit. Could this explain the squeeze bulb not firming up?
I do not have a clear filter on the fuel pump outlet.
Thanks Guys

 

[jerryjerry05]

IF???? the fuel is fresh???
You shouldn't have to add anything to it.
Adding SF is like adding soap to the system.
Stabil is a great product but not needed unless your letting the boat set for 3 months or longer.
The fuel doesn't breakdown that fast.

The ball not firming up, that can be the ball itself or the fuel pump and even the inline connectors.
Even a brand new ball can be bad right out of the box, I bought 3 Tempo balls and all were bad??

Depending on the pump type, the square seems to go bad/leak quicker than the old 8 shaped one.
Year? or a pic? helps?

The 70 depending on the year, some have a filter inline on the fuel system.
Like Jiggz suggests, a filter Fram G-2 G-3 G-12 one of these works well.

 

[Force39]

Got a fuel pump rebuild kit and installed . Went pretty good. Bulb still wouldn't pump up firm, but eventually got it started and ran fine. Came back to report my findings, but checked out Youtube first. Searched "boat fuel bulb won't firm up". Saw a couple different posts that said to make sure you hold the bulb with the arrow pointing up. Went down to boat and tried it. Pumped right up! Maybe I've been told that here at some point, but if so I didn't remember. Hopefully this will cure my restarts issues. If not I'll be back begging for help! Thanks to all!

 

[jerryjerry05]

The ball should work in any position??

 

[Force39]

https://www.youtube.com/watch?v=Mrt38-ulYFc https://www.youtube.com/watch?v=IPsqPnFkhAg Here are 2 of the youtube video's