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  1. Scott06

    Thru hull exhaust

    Marine rating on accessories has nothing to do with being hardened , what ever that meas. marine rating is for components designed to prevent electrical sparks and gas vapors from igniting. This challenge is quite different in an enclosed marine engine compartment vs an engine on a car or truck...
  2. Scott06

    Prop Suggestions Needed

    Ok so based on what you are showing for rpms and stated good running condition drop 2” in pitch
  3. Scott06

    1974 mercruiser 3.0 cylinder head interchange

    Yes you can if you can still use the existing manifold there is an adapter https://www.michiganmotorz.com/mercruiser-exhaust-manifold-adapter-plate-kit-high-output-3-0l-engine
  4. Scott06

    Carb or worse?

    No harm in loosening the valves and trying it, worst case it will clack and make some noise
  5. Scott06

    Prop Suggestions Needed

    Dont sweat the diameter that is for the prop designer to figure out. I belive the rule of thumb is 2" pitch decrease per 3000 ft of elevation increase . Was the boat ok with a 19" at sea level or close to it
  6. Scott06

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    ok good to know it usually the easy stuff. I had a sticking choke on my mercarb would foul the plugs pretty quick. You can force it open to test but if opening it made it run worse you are probably lean in the carb
  7. Scott06

    Thru hull exhaust

    two 45s on each side with marine hose in between to make them meet up . The post above gave some links or places like michigan motorz will have them. Have you had a boat with thru hull exhaust before? A lot fo folks end up hating it after a while .
  8. Scott06

    Prop Suggestions Needed

    I think you will loose 15-20% power at these higher elevations and your carb will need rejetting if it hasn;t been set up for these elevations. De rated for altitude you probably only are making 160 or so hp on a faily decent sized boat. Try a 15" pitch or if wakeboarding is your thing try a 4...
  9. Scott06

    Yellow sticky fluid from engine

    Yes you have water in the crank case, which fills up until it comes out the valve covers. How was it winterized? Usually this is from improper winterization and you end up with a cracked block typically under the heads in the lifter valley. Also can crack or rot out thermostat housing on...
  10. Scott06

    4.3 GXi-J with DPS-A howling sound

    Sounds just like my friends 4.3 has a distinctive howl
  11. Scott06

    Drive Housing Pit Filler?

    Glad to see you are using DP90, i blasted and primed my 65 gto with dp90 in 1993, almost zero bubble back of rust since then. Check the usage instructions, back in the day it required a fresh air supplied respirator. Of course i ignored this and then coughed fir three days
  12. Scott06

    VIDEO Help: Post Texas Freeze Leak

    Michigan motorz willa a replacement base engine for you
  13. Scott06

    Mercruiser 3.0 strange sound at low end acceleration

    Well at least it was something simple. Unfortunately on the 3.0 the belt gies through the front engine mount.
  14. Scott06

    1984 120 hp carb issue.

    first one is a guy who rebuilds pontiac tripowers (same rochester 2 bbl design you have) so use your factory float specs second one is from mikes carb parts he has lot of good videos on his channel but this one setting float height is not the best visually.
  15. Scott06

    What's the right boat prop help

    Sounds like it has a high five prop on it Given speed and rpms . Q has you steered correctly 19 or 21” pitch start with a black max or similar to get your bearings then can step up to something better if you like. Really depends on what you want to use the boat for
  16. Scott06

    2008 4.3 ltr mercruiser overheating alarm

    did you replace the temp switch that triggers the alarm? did you check your exhaust manifolds and elbows for clogging? This can restrict water flow mostly in salt or brackish water use
  17. Scott06

    1987 3.0 engine rebuild

    Best way to get more power out of a 3.0 is swap in a 4.3. if you want to use the newer head i think this adapter will make your existing manifold fit the newer head. https://www.michiganmotorz.com/mercruiser-exhaust-manifold-adapter-plate-kit-high-output-3-0l-engine
  18. Scott06

    1984 120 hp carb issue.

    Assuming choke fully open s, Most likely float level or too high fuel pressure both lead to higher bowl fuel level . Id start with float level and drop check or replace needle and seat Plus measure fuel pressure.
  19. Scott06

    Carbed Mercruiser 260 5.7L Missing Above 4000 RPMs

    yes I suspect you have some guage accuracy issues around 150 psi is new, unless you had water or gas in the high one I suspect thats an outlier. Typically I think you start getting dead cylinders below 120 psi. The carbon fouled plug is way rich I suspect that may be yoyur issue, although as...
  20. Scott06

    fuel pump frustration

    try googling carter marine fuel pump thats what lead me to summit.... https://www.summitracing.com/parts/crt-p4389 . None of the electric fuel pumps have the overflow tube as they dont have a diagraphm to rupture like a mechanical pump that requires somewhere to fuel safetly go. As nola pointed...
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