Attempting DIY repairs on my motor..after reading what must be every post about the topic, I'm breaking down to see if anyone has any new ideas to save the trip to the shop...thanks in advance, and thanks for all the great info I have already gotten from these boards!
I have a 97 force 120 on a 97 Astro 17ft bass boat..ran pretty well last few years but started bogging at WOT a few months ago. Here's the catch, she doesn't bog down every time, it's more like 2 out of 3 times. Sometimes she will get up and go like normal and run great pushing 40mph as usual. She might take off great at launch, or not, or after fishing for an hour, or not. I can give her throttle 2-3 times in a row and she bogs, then after idling another few minutes, I give her throttle and she responds.
Out of water, in the driveway on muffs, she runs and sounds great, starts, idles, never dies, in and out of gear smooth...so it seems like an under-load situation. In water, she starts fine and will idle all day, but when I try to get on plane, she doesn't have the power. Seems like a fuel starvation issues, but with the work already done, and the fact that sometimes, she does get up on plane, it makes me wonder if I am missing something.
What's been done since it first happened...
Replaced Stator, Trigger, CDI units and voltage regulator ( this work done as side job by mercury tech who thought it might be electrical / spark issue. I had used him to do my lower unit previously. Didn't fix the problem this time and I'm not comfortable going back to him to pay for more non-fix repairs)
replaced in-line fuel filter
re-built fuel pump
replaced squeeze ball
inspected all fuel lines, no issues or blockage, re-installed fuel lines with new clamps, zip ties to ensure no leaks
Carbs- took apart, replaced gaskets, cleaned, they were both super clean with no varnish at all..floats are good, no seating issues.
With motor running. sprayed gas/oil mix into carbs, and motor would begin to die, as it should
No gas tank venting issues, pick-up in tank is clear, gas is good/fresh (its a 50:1 oil gas mix)
Visual reed inspection when carbs were off..looks good, clean
Compression is 130-140 all 4 cylinders....got new plugs, they are all dirty after use, but not wet or oily.
carbs are synched, butterflies open equal at full throttle
removed prop, no obstructions..(.impeller was replaced 2 seasons ago)
I have not done any adjustments while on the water, just on muffs.
I guess I am hoping someone might be familiar with the intermittent bogging and might have any more ideas what to check.
Thanks again...
AZJamie
I have a 97 force 120 on a 97 Astro 17ft bass boat..ran pretty well last few years but started bogging at WOT a few months ago. Here's the catch, she doesn't bog down every time, it's more like 2 out of 3 times. Sometimes she will get up and go like normal and run great pushing 40mph as usual. She might take off great at launch, or not, or after fishing for an hour, or not. I can give her throttle 2-3 times in a row and she bogs, then after idling another few minutes, I give her throttle and she responds.
Out of water, in the driveway on muffs, she runs and sounds great, starts, idles, never dies, in and out of gear smooth...so it seems like an under-load situation. In water, she starts fine and will idle all day, but when I try to get on plane, she doesn't have the power. Seems like a fuel starvation issues, but with the work already done, and the fact that sometimes, she does get up on plane, it makes me wonder if I am missing something.
What's been done since it first happened...
Replaced Stator, Trigger, CDI units and voltage regulator ( this work done as side job by mercury tech who thought it might be electrical / spark issue. I had used him to do my lower unit previously. Didn't fix the problem this time and I'm not comfortable going back to him to pay for more non-fix repairs)
replaced in-line fuel filter
re-built fuel pump
replaced squeeze ball
inspected all fuel lines, no issues or blockage, re-installed fuel lines with new clamps, zip ties to ensure no leaks
Carbs- took apart, replaced gaskets, cleaned, they were both super clean with no varnish at all..floats are good, no seating issues.
With motor running. sprayed gas/oil mix into carbs, and motor would begin to die, as it should
No gas tank venting issues, pick-up in tank is clear, gas is good/fresh (its a 50:1 oil gas mix)
Visual reed inspection when carbs were off..looks good, clean
Compression is 130-140 all 4 cylinders....got new plugs, they are all dirty after use, but not wet or oily.
carbs are synched, butterflies open equal at full throttle
removed prop, no obstructions..(.impeller was replaced 2 seasons ago)
I have not done any adjustments while on the water, just on muffs.
I guess I am hoping someone might be familiar with the intermittent bogging and might have any more ideas what to check.
Thanks again...
AZJamie