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2001 225 hp Optimax bogs down above 4500 RPM, any thoughts?

R

Ryan Cail

New member
I have a 2001 225 Optimax that bogs down above 4500 RPM. New fuel lines, filters, batteries, and water seperator installed. Also has a fresh tank of gas. Recently replaced the air compressor filter. Here's the kicker- it doesn't bog down with the cowling off. No obstructions in the cowling, no alarms go off indicating a temperature issue. What do you guys think?
 
Re: Optimax bogs down above 4500 RPM, any thoughts?

It could be a minor exhaust leak. With the cowling on it could be sucking "exhaust" that contains less oxygen than regular air.

I've never seen that particular quirk on an Opti, but there was some small Honda's that developed a crack in the exhaust plate (chronic problem throughout the production run) and caused the exact issue you note - and once you pulled the cowl to troubleshoot, the bogging cleared up.
 
Re: Optimax bogs down above 4500 RPM, any thoughts?

galamb said:
It could be a minor exhaust leak. With the cowling on it could be sucking "exhaust" that contains less oxygen than regular air.

I've never seen that particular quirk on an Opti, but there was some small Honda's that developed a crack in the exhaust plate (chronic problem throughout the production run) and caused the exact issue you note - and once you pulled the cowl to troubleshoot, the bogging cleared up.
Click to expand...

Thanks for the idea of where to look! I've had a couple other people suggest an exhaust leak, but I wasn't sure where to start troubleshooting. Do you happen to know where the exhaust plate is and how easy a job it is to inspect?

Thanks!
 
Re: Optimax bogs down above 4500 RPM, any thoughts?

The exhaust plates / covers are at the back between the cylinders.-------------------Also a gasket between the engine block and exhaust housing.
 
Re: Optimax bogs down above 4500 RPM, any thoughts?

I think the exhaust is cast right into the block (between the heads as noted above), so no covers on this particular model (however, could be cracked so definately worth checking), but there are two gaskets where the powerhead attaches to the "leg" - on above and one below the exhaust plate (which is sandwiched between the motor and the exhaust housing (leg)).

To get a good look at the exhaust (cover) you have to remove all the coils which are fastened to it (a pain) and then you still may not see much unless it's a considerable crack. To get at the base gaskets you have to completely remove the powerhead (smaller job than it sounds, but still quite intensive if you are trying to do it in the driveway).

I would probably be inclined, at this point, to take it to a shop and spend the cost of an hours labour to have them check for a leak - at least then you would either 1) rule out a leak or 2) know where the problem lies and decide from there whether to have a pro deal with it or if you feel comfortable breaking out the tool box yourself...
 
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Re: Optimax bogs down above 4500 RPM, any thoughts?

galamb said:
I think the exhaust is cast right into the block (between the heads as noted above), so no covers on this particular model (however, could be cracked so definately worth checking), but there are two gaskets where the powerhead attaches to the "leg" - on above and one below the exhaust plate (which is sandwiched between the motor and the exhaust housing (leg)).

To get a good look at the exhaust (cover) you have to remove all the coils which are fastened to it (a pain) and then you still may not see much unless it's a considerable crack. To get at the base gaskets you have to completely remove the powerhead (smaller job than it sounds, but still quite intensive if you are trying to do it in the driveway).

I would probably be inclined, at this point, to take it to a shop and spend the cost of an hours labour to have them check for a leak - at least then you would either 1) rule out a leak or 2) know where the problem lies and decide from there whether to have a pro deal with it or if you feel comfortable breaking out the tool box yourself...
Click to expand...

Thanks for the detailed response. I will probably be taking this one to the pros. Thanks again for all the help.
 
Re: Optimax bogs down above 4500 RPM, any thoughts?

I have a 2001 ,225hp mercury optimax and it bogs down after running at crusing speed 3500-4200 rpms for 20 minutes. Changed spark plugs, wires,and fuel filters. Cant figue it out. I use the scan tool and did all the electrcal testing and no faults came up, eveything passed. Does any one have any ideas on this problem.Also it has a ruf idel. Thanks.
 
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