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87b 23 Bogs in the waves

threeriversdog

New member
"Great Site and I hope someone

"Great Site and I hope someone can help me. My 87' 20ft Thundercraft Malibu is acting up. At the beginning of the season I put in new points, cap, plugs and wires. It got a new carb last year. I filled it with 93 octane on saturday and took it to the river. It ran great almost all day. Although when I first started out I notice a little miss in the engine but that went away. Later on at about 1/2 a tank it started bogging/missing/losing power when ever I crossed wake. Like the choke was closing or the coil wire was loose. I cant figure it out though. It runs great until the boat starts to bounce then it misses and comes of plane. Any suggestion at all ???"
 
"Thanks for responding so quic

"Thanks for responding so quick. Is that the cylindrical clamped unit that is on the left side of the engine? Because I took that thing apart, inside was a paper filter and a spring. The black rubber seal on the bottom seemed to be in good shape. I could not see anything wrong with that. How would the water/fuel seperator only cause problems when the boat is bouncing wouldnt be a problem all the time?"
 
"If the problem is instant as

"If the problem is instant as You hit the waves it is normally electrical, loose wire/ground somewhere on the engine or instrumentpanel. May even be the rev counter itself, kill/safety switch. If the problem is delayed some seconds it may be fuel related."
 
The problem is slightly delaye

The problem is slightly delayed and goes away after the boat stops bouncing through the waves. The motor never cuts out completely. I checked most things that I know how to check. Could it be the choke linkage?
 
"Also, when it was doing this

"Also, when it was doing this waves bogs thing I took of the flame arrestor to check the carb with motor freshly turned off. There was alot of smoke around the carb throat and down inside it. The smoke was black and the inside of the carb looks burned up a little."
 
Did You adjust the points by d

Did You adjust the points by dwell setting or just opening? Did You check the ignition timing after the points change?
 
"I had the new points put in a

"I had the new points put in at a shop they timed it also. The boat has ran fine all summer up until the end of the day Saturday. Funny thing, I have had to have the points replaced and get it timed for the past two years and I have had it for two years."
 
"There is a lot of Pertronix t

"There is a lot of Pertronix talks on this board, at least it eliminate the poin/condensator problems. If the points gets burned, it is normally a condensator problem."
 
"Guys, I ran the boat this we

"Guys, I ran the boat this weekend. It ran great for an hour at plane. Then the boggin problem began again. I suspect it is a heat related problem. The bottom of my fuel pump housing is getting very hot. The hard fuel line into the carb is not overly hot but, the engine is definetly starving for fuel as the heat builds. I am running 93 octane and I suspect that I am boiling fuel in the fuel pump. When the motor is under load(even turning the tiller hard side to side causes the bogging problem). I will replace the fuel pump this week. I thought maybe the float also but the carb is less that a year old. I will keep you all posted. Thanks for all of your advice."
 
Check the anti siphon valve at

Check the anti siphon valve at the ank top. If stuck it might restrict fuel flow. Can You hook a vacum meter in the line before the pump?
 
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