4.3 mercruiser bogging a bit at high rpms...what is causing it?
 

My 182 Shabah has the 4.3 liter 190hp in it. I have had it out 8 or 9 times this season with no issues. On our last trip, the engine was bogging down just a tad at high rpms. Idled great and ran all day, but started to bog or hesitate just a bit when pushed over 3500rpms. Top speed down a few mph also. Seemed like a fuel issue to me so I bought a new fuel water separator and will try that. Anyone have a similar problem? Any ideas on what else to try?

Re: 4.3 mercruiser bogging a bit at high rpms...what is causing it?
 

cant rilly help ya with the problem but i was hopen you might be able to help me. ive got the same boat as you and im rilly thinking about going a different prop. im able to get 35 mils per hour at 4800 rpms with a 21 pitch prop. was woundering what prop you have and are you able to run full throt with out over 4800 rpms. thx for the time.

Re: 4.3 mercruiser bogging a bit at high rpms...what is causing it?
 

hi Eick. Please dont hi-jack someone else's thread to get an answer for your own problem. I see that you have posted your issue in the Prop section where it belongs so we will deal with it there.

Re: 4.3 mercruiser bogging a bit at high rpms...what is causing it?
 

Eick - I am running a 19 pitch aluminum prop and was hitting about 49mph at 4900 rpms until the bogging issue. Now the best I see is 46 mph at 4400.

Re: 4.3 mercruiser bogging a bit at high rpms...what is causing it?
 

Hello Bbrophy58, my boat would start up fine, idle no problem but when I accelerated it began to bogg. What I found was two of my spark plugs were cracked.....changed them out and boat runs great. Im no boat mechanic, but thats what helped my situation. Hope this helps.

Re: 4.3 mercruiser bogging a bit at high rpms...what is causing it?
 

AZboatman - Well I replaced the plugs, wires, distributor cap and rotor and that solved the problem. Runs perfectly now with no bogging. None of the plugs looked cracked, but replacing them definitely helped. I also sprayed a bunch of carb cleaner into my carburetor. Glad it was nothing major!