Hashburyfl
New member
I have a 90 hp 1999 mariner and after running it for 10 to 15 mins at 85% throttle it seems to bog down. Bog down is probably the wrong phrase it feels and sounds like the throttle is being lowered to random points. I can keep the boat on plane probably around 40% throttle and not have the issue happen.
There were 2 things I did before this started happening. I may have grazed a sandy/muddy bottom at a very slow speed. I couldn't really tell if I hit or not but there is the possibility I kicked up some mud with the lower unit.
The second thing I did was change the fuel water separator and I only filled it between 1/2 to 3/4 full. I'm not sure if the engine could suck air from there or not. I did cut about an inch of hose from the filter as the inner liner was a little stretched.
Things I've done since:
I pumped some of the gas out to make sure there was no water in it. I went ahead a replaced the spark plugs (haven't ran it since), and they didn't seem too bad. I checked the compression and it was all within 2psi. I inspected the fuel hoses as best as I could (hose to the tank runs under the deck). The bulb and its connectors seem good, the connector to the engine has some wear on it but seems good too. I ran some seafoam through the engine. I took the fuel filter out and cleaned it with seafoam (haven't ran it since), but it also seemed clean.
I feel like it's a fuel issue but this is not my area of expertise and would really like to hear some ideas or suggestions on what I should try trouble shooting next.
There were 2 things I did before this started happening. I may have grazed a sandy/muddy bottom at a very slow speed. I couldn't really tell if I hit or not but there is the possibility I kicked up some mud with the lower unit.
The second thing I did was change the fuel water separator and I only filled it between 1/2 to 3/4 full. I'm not sure if the engine could suck air from there or not. I did cut about an inch of hose from the filter as the inner liner was a little stretched.
Things I've done since:
I pumped some of the gas out to make sure there was no water in it. I went ahead a replaced the spark plugs (haven't ran it since), and they didn't seem too bad. I checked the compression and it was all within 2psi. I inspected the fuel hoses as best as I could (hose to the tank runs under the deck). The bulb and its connectors seem good, the connector to the engine has some wear on it but seems good too. I ran some seafoam through the engine. I took the fuel filter out and cleaned it with seafoam (haven't ran it since), but it also seemed clean.
I feel like it's a fuel issue but this is not my area of expertise and would really like to hear some ideas or suggestions on what I should try trouble shooting next.