Fun at 5.5 mph this weekend :)

[gunterm]

So I finally took the boat out this season, was very excited when running up the throttle however my heart sank as soon as she started to stutter out.

It starts up and runs fine and at idle, and also is pretty good up to about 5-6 mph, then it starts stuttering as if it's out of fuel. It will also go from idle to full throttle and run good for about 10 seconds before it starts chugging again.

Although limited to a slow speed we still had fun!

I'm hoping to figure out what this is, we checked the fuel lines on the boat and everything seems fine there. After getting home I realized there are slightly different spark plugs in it, the ones from my last outing where it ran great were B8S and the ones in it now are B7HS.

 

[foodfisher]

Re: Fun at 5.5 mph this weekend

Be sure fuel tank is venting.

 

[gunterm]

Re: Fun at 5.5 mph this weekend

At first I thought that too and ran back to open it up, but it made no difference unfortunately...

 

[crazyinkc]

Re: Fun at 5.5 mph this weekend

Make sure your fuel lines have no leaks. A leaking line will cause loss of prime. Try pumping the primer bulb when it poops out again and see if she revs back to life. Make sure you are in a safe position and someone is behind the wheel. BTW, I have a 10hp Chrysler on my 20ft Playcraft pontoon and we only do 6 to 8mph (depending on load and wind) and we always have a blast. I use my runabout for speed

 

[gunterm]

Re: Fun at 5.5 mph this weekend

Since the fuel line assembly is cheap maybe I should just replace it... What really sucks about this problem is I can't see it until I get on the water.

 

[crazyinkc]

Re: Fun at 5.5 mph this weekend

Replace the primer bulb too. The check valve might be bad and allowing fuel to drain back. Mine was bad and the bulb was deteriorating on the inside. I think the valve was getting little chunks of rubber stuck in it.

 

[gunterm]

Re: Fun at 5.5 mph this weekend

Thanks for all the tips! I bought a complete new hose assembly (universal type, includes primer bulb) and will be putting it on this week and we'll see how things pan out on Saturday. I don't suppose there's a way to test if this was the problem before putting it on the water?

 

[87blf125]

Re: Fun at 5.5 mph this weekend

i would also clean the carbs

 

[milehighboater]

Re: Fun at 5.5 mph this weekend

the only way to test them is if they are not holding pressure. if the bulb goes soft or never firms up there is a good chance you have found the problem. Also if the fuel lines are getting soft they may be coming apart from the inside and clogging up the check valve. If you find any debris it may have been the line too. Sorry there is no sure fire way to know if it was it without trying it out. You maybe having multiple smaller problems going on and you might have just fixed one of them. Try it out and good luck.

 

[gunterm]

Re: Fun at 5.5 mph this weekend

The idle speed ramped way up after replacing the hose so I have a good feeling. On a positive note, nothing changed since my last outing at 25-30 mph so I'd hope a bunch of stuff didn't break and it was just the fuel assembly.