I purchased a 1997 Honda 8HP BF8A outboard for my sailboat last year from a friend. It worked FANTASTICALLY all last season, it was able to push my 23' sailboat at hull speed, at around 7 knots. After storing it for the winter, I decided to take it to a local marine shop in April who services Honda and have them tune it up as it took 6 to 10 pulls to start last season. They charged me $275 for a carb clean and lower unit oil replacement. EVER since that work in May, I have been unable to get full speed out of this engine (though it does start in 2 to 3 pulls now). It sounds like it is getting to maybe 1/3 RPM and pushes the boat along at about 2.5 knots. Since May, I've taken the engine back out to the boat about 4 times after mechanics claimed it was fine. Each time, the engine runs just fine, but won't go to full throttle while in gear, even at the slip I can rev it right up in neutral, no issue. But, in gear, no dice. One time while I was testing it, I took it out about 3 miles into Lake Michigan and it suddenly LEPT up to full RPM and stayed that way for a good 20 minutes, after I turned the engine off and started it back up, it hasn't done that again, it remains at low RPM in gear and just pushes the boat along like it's struggling.
When I put the engine in a barrel and put it in gear, it revs up to what sounds like full throttle just fine. So the issue is hard to reproduce by the mechanics who all just stick it in a tub. It seems that it only has the issue when trying to actually push the weight of a boat rather than just stir 40 gallons of water.
Things I've tried so far:
1. I've had 3 mechanics looks at it so far, 1 says nothing wrongs with the engine (but he put it in a barrel and that's it), second mechanic put it on a small fishing boat and he observed that it's not getting to full RPM (but it sounded like it was going faster than my sailboat, which is 23 ft compared to his 13ft fishing boat), but he is unable to explain why and gave up, third mechanic has had it two weeks and so far has been unable to reproduce the problem in a barrel, he SAYS he will take it to a boat and test it, we will see.
2. I have replaced the fuel in the tank
3. I have replaced the fuel line from the tank to the engine
4. I have replaced the Honda fuel line connector ON the engine
5. I have replaced the fuel filter
6. The carb was cleaned in May by a Honda dealership
I am at my wits end with this engine, It's been out of service since May, so I've lost the entire summer waiting on mechanics to run it in a barrel and then tell me nothings wrong. Any insight into this issue would be greatly appreciated!
When I put the engine in a barrel and put it in gear, it revs up to what sounds like full throttle just fine. So the issue is hard to reproduce by the mechanics who all just stick it in a tub. It seems that it only has the issue when trying to actually push the weight of a boat rather than just stir 40 gallons of water.
Things I've tried so far:
1. I've had 3 mechanics looks at it so far, 1 says nothing wrongs with the engine (but he put it in a barrel and that's it), second mechanic put it on a small fishing boat and he observed that it's not getting to full RPM (but it sounded like it was going faster than my sailboat, which is 23 ft compared to his 13ft fishing boat), but he is unable to explain why and gave up, third mechanic has had it two weeks and so far has been unable to reproduce the problem in a barrel, he SAYS he will take it to a boat and test it, we will see.
2. I have replaced the fuel in the tank
3. I have replaced the fuel line from the tank to the engine
4. I have replaced the Honda fuel line connector ON the engine
5. I have replaced the fuel filter
6. The carb was cleaned in May by a Honda dealership
I am at my wits end with this engine, It's been out of service since May, so I've lost the entire summer waiting on mechanics to run it in a barrel and then tell me nothings wrong. Any insight into this issue would be greatly appreciated!
As an update, received a call from the current mechanic looking at it, and despite charging me $350, he can't fix it. He was able to at least observe the issue when he put it on a boat, he said it ran up at first and then died off to around 75% after it warmed up. Likely because it was a much smaller boat than mine. He scoped it and said there is some scoring on the cylinders. He said that compression tests showed it getting somewhere around 70-80 lbs versus the 150 or so it should be getting. He said during testing they messed with the mixture to confirm it isn't a fuel issue. He suggests putting some cleaner in it and running it out to see if that helps, but other than that, he is stumped.