89 Merc 4.3 Mercarb hesitation out of the hole

[tbeaze24]

Just rebuilt the carb, and it really idles a lot better, and is more responsive. Problem is, I have to idle up to about 21 or 2200 rpm, then hit it. If I go from dead idle which is about 700 rpm, it stalls out, well you have to play with it to keep it from stalling out?? Any help?? Thanks, Tim

 

[Gary H NC]

Re: 89 Merc 4.3 Mercarb hesitation out of the hole

I would recheck the float setting and look close at the accelerator pump. Sounds like its starving for fuel.
About all you can do at this point is recheck everything.

 

[Gary H NC]

Re: 89 Merc 4.3 Mercarb hesitation out of the hole

No update Tbeaze?

 

[tbeaze24]

Re: 89 Merc 4.3 Mercarb hesitation out of the hole

Hey Gary, Well I took it out yesterday. OMG, it was amazing what a new fuel pump, carb rebuild and all will do, it runs great. Still having to play with the throttle a little, but I am thinking it is good enough that I am not going to tear apart the carb again. I also found out that,when the carb is clean, and everything is running right, it sucks down a hell of a lot more gas, which is only natural, seeing how it was turning about a 1000 more rpm's. I also found out that my fuel gas is fairly forgiving, it was showing about an 1/8 below empty before it ran out. There I am flying down the river, and it was running so well I just kept going. Well needless to say, I went about a mile and a half to far. LOL,,,,I ran out of gas and had to get towed back in. Any way, it is running great, pops out of the whole and trims out rather quickly. Top speed on the gps was 43.5 with a 17 pitch prop, at about 3900 rpm's. I could go to 15 pitch and probably be right in my wot rpm range, but I am probably just gonna leave for the fuel mileage. Thanks for all the help guys. Happy Boating, Thanks Tim8)

 

[180shabah]

Re: 89 Merc 4.3 Mercarb hesitation out of the hole

If everything else is working properly (including the tach) then 3900 RPM at WOT is TOO low. This is creating alot of excess stress on your engine. also if you have a 4bbl carb the extra load will always have you running witht the secondaries open, this hurts not helps you economy.

 

[Gary H NC]

Re: 89 Merc 4.3 Mercarb hesitation out of the hole

Its a 2 bbl 180shabah,
Tim,Good to hear! I didn't know you had to replace the fuel pump also. That engine should turn 4400 to 4600 rpm with a 2bbl carb. Check your linkage that its opening up all the way. 43 mph sounds about right for that setup.possible the tach is off.
Just pulled my carb yesterday for a rebuild.Gives me something to work on...lol. It was running ok just a little rough idle sometimes.
Glad your back on the water! Watch that fuel guage!!8)8)

 

[tbeaze24]

Re: 89 Merc 4.3 Mercarb hesitation out of the hole

I can understand about the WOT being lower than what it should be, but at the same time, when it was starving for fuel and I was messing around with, it sounded like it was more stressed then, than it is now. I really think my tach my be off, I have been around enough boats before to know what one should sound like. It defienately did not sound right before, the way it sounds right now, it is almost at a roar, but still purring, if you all understand that. It pulls strong out of the hole, and then levels off as I trim it out. Thanks for the help guys, and I am going to try and get a tach or borrow someones from there shop. Keep you updated, Tim