85 3.0 Hesitation

[chevydan04]

So I took my boat out and have a minor/questionable issue. Its seems that when I punch the throttle to get it going, it bogs out and dies, in both forward and reverse.

But when I ease it up slowly apply throttle pressure it has no problem getting to plane. It runs great when in WOT.

This is annoying as I was unloading/loading the boat at a ramp where I had a current pushing the boat towards the docks.

The fuel in the boat is from last year. I was going to run it out of gas and put fresh 89 Octane gas in it. (In Delaware all gas is %10 ethonal)

Also I have not replaced the old spark plugs.

I am thinking that I need to replace fuel filters and water seperator.

Also my dwell is at 29.4 as measured by the nice multimeter I have.

And my timing at idle is set at 6 Degrees BTDC.

Boat Idles at 520 RPM also measured by multimeter with inductive pickup. (and the tach on the boat reads roughly the same)

Motor is Mercruiser 140 I/O, 3.0 4cyl

Any thoughts or ideas?

 

[achris]

Re: 85 3.0 Hesitation

Just one.... Accelerator pump in the carb...

Chris........

 

[chevydan04]

Re: 85 3.0 Hesitation

Thanks Chris I will look into that and keep you updated.

 

[crazyinkc]

Re: 85 3.0 Hesitation

If the accelerator pump doesn't fix it, you may need to tune your idle mixture. I would tune the mixture before I did the pump but thats just cheap old me.

 

[fat fanny]

Re: 85 3.0 Hesitation

Yes! I agre w/ crazy do what doesn't cost anything first. Go to the adults only at the top of this forum and read up on the why my boat doesn't reach WOT ( trouble shooting guide) But more than likely like I found out last year the carb needs rebuilt pretty easy and only cost me just under 50.00 did it myself kit from aftermarket marine.com and a can of berrymans carb cleaner (autozone 19.50) And about an hour and a half of my time well worht it.

 

[achris]

Re: 85 3.0 Hesitation

And how much does it cost to pull the cover of the carb and look down the hole while someone else push the throttle forward?
Or if you're on your own, remove the throttle cable and do it all at the carb....That, my friends, is how you check an accelerator pump!!! Don't you guys know ANYTHING????

 

[Don S]

Re: 85 3.0 Hesitation

Boat Idles at 520 RPM also measured by multimeter with inductive pickup. (and the tach on the boat reads roughly the same)

Set the idle rpm up to 650 to 700 rpm in forward (not tied to dock) where is should be and readjust the idle mixture. Bet it works fine after that. Too lean and it will hesitate, same with too rich.

 

[chevydan04]

Re: 85 3.0 Hesitation

To keep you updated...

I took the boat out yesterday after I checked the pump by looking in the carb hole, I noticed it seemed to work fine, also the carb is very clean. It was rebuilt last year.

I drove the boat about 1.5 miles down a river that leads to the DE bay and back. I also put some fresh gas in it prior to the outing.

Well my wife asked me to go faster to get back to the ramp, and wow. I didn't have the throttle all the way down but almost, at 4000 rpm, the I was moving. It did it very smoothly.

Got back to the ramp and dropped my wife off on the dock put the trailer in, and after that I got back in the boat and messed around with dumping the throttle to wide open quickly, at first it didn't want to, but then it started acting normally.

I believe I just need to use the boat... what do you think?

Also picked up new plugs today, so gonna install those before the next outing.

Thanks for your help and input everyone...

 

[achris]

Re: 85 3.0 Hesitation

....I believe I just need to use the boat... what do you think?...

Very possible. I've always said that it's not USING a boat that kills it, it's NOT using a boat that kills it.

Chris......

 

[chevydan04]

Re: 85 3.0 Hesitation

put new spark plugs in. No more hard starts, I pump the throttle one time, back to neutral turned the key and instant start.