Honda trembles and won't rev above 4500

[Tom turkey]

It ran fine last seasons and after running wide open on a run in bogged and trembled down to 4500 rpm and had no power and was running rough.. I knew it had the tiny bit of water in the lower as I was going to change the seals. I changed the seals ran it a bit and then drained and changed the gear oil again to get rid of the last little bit of milky. Went for a run and it did the same thing for about ten minutes and then all of a sudden it started purring and reved up to 5600 rpms and ran great for like ten minutes and I was about to head in and then it trembled again and wouldn't run over 4500 all the while trembling and not having the normal power at 4500 rpms when it runs smooth. I had thought that the milky gear oil was frothing up and causing it to bog but I guess not the case..any thoughts be great

 

[gm280]

Well Tom Turkey, interesting handle, Sounds like you may have a couple issues. Sounds like the lower foot section has a leak and will need to be resealed, but the RPM issue could be ignition or even fuel issue. I would start by checking the entire fuel system first, being how that would be the easier system to verify first. Make sure everything from the tank to the primer bulb to the fuel pump to the carb(s) (if it has any) to see if that all is working perfectly.

You didn't state the year, HP, or model number of your engine, and that would help diagnose your problems. JMHO

 

[Sylva-Ranger]

Look like sometimes missing one cylinder ? How many cylinder ?

 

[ahicks]

I can share that the "trembling" and running at 4500 rpm likely has nothing to do with milky lower unit oil. Those would be 2 totally different issues. When was the last time the engine was treated to a new set of spark plug? If it's been a while (in engine run time terms, not calendar terms) a bad plug could cause it to behave as you describe.

 

[Tom turkey]

Thank you for the replies it is a 1998 carbureted Honda 40 hp 3 cylinder I change the spark plugs at the beginning of last season but I have done a lot of crabbing and long running at low idols I did treat to gas last season last trip out to put in the stable and seafoam but I didn't drain it or anything during winter and seemed to run fine do you think any additives like seafoam or ethanol treatment would help

 

[Tom turkey]

It idols in neutral and revs up real smooth but under load breaks up would that still be possibly spark plugs

 

[Tom turkey]

BF40 4 stroke

 

[Tom turkey]

Any more thoughts on why it ran trembling for ten minutes and then ran fin for ten minutes and then back to breaking up

 

[gm280]

Could be fuel issues or even timing issues. At this stage, most anything could cause your problems. And because of that, you need to check and eliminate things as you go over everything.

I would try fresh fuel and look at the carbs. And if you can't remember the last time you rebuilt the carbs, now would be a good time. Look at the fuel lines all the way from the tank to the fuel pump. You could even be getting fuel line deterioration and bits of fuel line is breaking off internally and clogging up the carb jets.

Everything has to be checked and verified at this point. But do that checking in a systematic way. In other words, start at the fuel system and check everything from tank to carbs. If everything there looks good, mark that off the list as a possible issue.

Then check the spark system. Everything that produces the ignition needs to be checked and tested. Go in a stepped troubleshoot method and mark things off as you verify they are good. JMHO

 

[iggyw1]

Just seen this today. Hopefully you have the issue resolved, but if not, add some Sea Foam to the gas to help clean the carbine out of the [power head. That will help you out. I use it religously and it worked wonders when I was having the same issue a few years ago. Try it.