Please help a wannabe mechanic

jsalz

Petty Officer 2nd Class
Joined
Jun 12, 2008
Messages
103
It seems I can make the easiest of jobs oh so difficult.
96 115hp 2+2
She was running great all summer but then for some reason, she started bogging at mid throttle. Runs great at WOT but when I cut her back to cruise around 3000 rpms, starts to bog like it was starving for fuel. If I immediately hammered down, right back up to WOT like nothing.
So I've had boat 3 summers and winterized properly and treated her well with good oil and good fuel. First thing I tried(because it was easy and cheap) was new fuel filters. No help at all. Runs like a champ wide open but bogs at mid throttle.
So the next thing I try (suggested here, and cheap) was to rebuild fuel pump and accelerator pump. Seemed pretty straight forward. Problem is, after fuel and accelerator pump rebuild, it's worse. Now it will idle and run slow all day. When I put the hammer down, she takes off and dies about 15 secs later. So here's my questions.
1. What would cause the OB to run fine at WOT but not at mid throttle?
2. What do you think I screwed up when rebuilding pumps? Bad fuel line connection? Bad reassembly?
One thing I did notice is that the accelerator pump has two mounting slots. I should have paid more attention when I took it apart but there is some allowance for where it can be mounted.
3. Where should the button on accelerator pump be when in neutral. Right against the (name?). Slightly below? I have the shop manual but it only describes its function but no details about testing or installation.

So that's it thanks for looking. I'll spend about 1-2 more days trying to figure this out myself or with the help of anyone here. Otherwise, off to the pros.
 

jsalz

Petty Officer 2nd Class
Joined
Jun 12, 2008
Messages
103
Oh yeah, also replaced plugs because they were 3 years old and again, pretty cheap and easy. Lol
 

gm280

Supreme Mariner
Joined
Jun 26, 2011
Messages
14,592
jsalz, I personally start with buying and rebuilding the carb(s) before doing anything else. If even a little piece of dirt gets into the low speed jet or even the high speed jet, those conditions will happen. So that would certainly be my first thing to do... JMHO!
 

Mi duckdown

Commander
Joined
Apr 14, 2007
Messages
2,575
What gm280 posted. Everybody tells you to blow air thru all the carb passages. I do one step better. run 25/30 lb. mono fishing line thru all passage to make sure there are no blockages. just ME
 

TD_Maker

Chief Petty Officer
Joined
Aug 31, 2005
Messages
564
No doubt. Clean and / or rebuild the carbs. MI Duckdown is also correct, and its a nice technique, but personally I have used the little wire you find on bread ties with great success. Hey, to each his own...whatever works. Bottom line is that you probably sucked some crap into the carbs and they just need to be cleaned.

I may have one more trick for you. Try some SEAFOAM in your fuel system and run the boat around the lake. Are you running from remote tanks? If so, dump a whole can of SeaFoam into your 6 Gallon tank and run the motor. I have seen this stuff do some amazing thing. I use it regularly in my boat, and my motorcycle.
 
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