85 3.6 V6 OMC stringer poor or no throttle response/bog high altitude when in gear

[Friendliest_catch]

Hey everyone.

I got this boat about a month ago and finally finished doing some large and expensive repairs.

When I bought it, it ran great and shifted smooth with good throttle response at sea level. Now at 5k feet where I live, if I shift fwd or reverse it bogs and provides no throttle response until I pump it in neutral a few times (no problem with RPM or throttle in neutral except slightly delayed response) let it return to idle, move lever to fwd and slowly let the the throttle advance.

Sounds like a textbook case of too much fuel.

Any recommendations on where to get high altitude jets and if I should adjust timing ? Or something that will at least not bog at 5k feet but will work okay around sea level? I will use it 80 percent at 5k and 20 percent lower down to sea level.

I also get a ticking when under load which goes away once I place it back in neutral which seems odd...ticking corresponds with RPM.

I'm new to boats but not to engines and carbeurators. I am fairly inexperienced with the 4v carbuerator on this OMC and not sure if the marine version shares the same pieces as the chevy v6 version as far as jetting goes ..

Thanks for all of the help in advanced!

 

[alldodge]

Hey @kenny nunez @Lou C

 

[Lou C]

Do you have a Rochester Quadrajet? If so I’d go over to Cliffs High Performance and ask on their forum. Not only will he know he also sells the parts you might need. Your problem may be the fact that the air density is so much less at altitude and your fuel mix which is calibrated for sea level may be too rich but first do a basic tune up (points, condenser, cap, rotor and plugs). The condition of the old plugs will give you a sense if the engine is actually running too rich (dark deposits on the center electrode insulator)...

 

[Friendliest_catch]

Do you have a Rochester Quadrajet? If so I’d go over to Cliffs High Performance and ask on their forum. Not only will he know he also sells the parts you might need. Your problem may be the fact that the air density is so much less at altitude and your fuel mix which is calibrated for sea level may be too rich but first do a basic tune up (points, condenser, cap, rotor and plugs). The condition of the old plugs will give you a sense if the engine is actually running too rich (dark deposits on the center electrode insulator)...

Il do that. Thank you for the help.

 

[Howard Sterndrive]

clean your flame arrester

 

[Scott Danforth]

go thru the carb

service the points. make sure to use a dwell meter. without a dwell meter, you are only doing a half-arsed job.

ticking could be bad ignition component (spark snapping) or detonation (your motor eating itself) or lean rattling (your motor eating itself)

 

[Lou C]

yep

 

[Friendliest_catch]

clean your flame arrester

Flame arrestor was disgusting. Melted away gunk with carb cleaner dip and it's sparkly new now. Improved it by a reasonable amount, but still not back to ideal running condition.

I will use a dwell meter and check next.

I also will need to replace the fuel filter as it being clogged may also be suspect... I believe the carb is running rich in low RPM and leaner in high RPM...possibly causing my confusing performance issues.

When pumping the throttle the fuel doesn't squirt into carb until the 2nd or 3rd pump and even then the spray is more of a trickle. Normal? I would expect at least some velocity .

Found that I needed 7 pumps to even get it started the other day after sitting 1 day after boating. I thought the carb had finally gotten stuck open internally somewhere and was flooding the engine, but really it was fuel starved so it wouldn't turn over.

Gasket kit is also on the way for the carb.

Small oil leak around fuel pump. Found there mayb be a hole in block on passenger side(possibly) that you can put a bolt in that may leak oil under high rpm.

I find that the "ticking" goes away at idle from advancing timing a degree or so. When this advance is made however, the engine does not run well at any other position out of idle.

I marked dist position and advanced dist slightly until rpm stop increasing at idle, then backed off slightly. The engine sounded great, but when throttle Is advanced and placed into gear it bogs produces little power until timing is retarded slightly. I left it back at the retarded position and it runs well, but with the audible ticking through most RPM .

Other notes :
*runs worse when cold. Requires warm up period in idle before able to advance throttle without bogging in any gear except neutral
*haven't checked spark plugs since last run. Will check when I return home from work trip to verify suspicions ..

Definitely getting closer to solving the issue with the help of everyone here !!