Search results

  1. Sea Rider

    Surprising Prop Test Results - can you guess which prop worked best?

    Yep, that seemed to me. Haven't have a chance to have a look at the Prop Calculator. Made a new wot test. The max achieved speed going full 5700 revs was : 41.5 KPH or 22.41 NMPH (knots) Prop calculators speeds seems are too positive, that speed was reached on a near lab water course, that's...
  2. Sea Rider

    Nissan/Tohatsu throttle cam removal/upgrade to 15hp, timing question, w/p questions, dead CDI tip

    Don't know why you like continuing messing with the whole engine if you haven't swapped 15 cam, right ? Forgot to mention that idle rpm must be slight decreased with carb's idle screw to lower engine's revs to a point that when lever is in forward gear while pushing combo engine doesn't die from...
  3. Sea Rider

    Nissan 9.9 prop ??

    Speculating about engine condition is the best way to lose precious boating time when first thing you need to do is troubleshoot the current prop to know its working condition. If found ok work from there.. OTHO, he's running a boat rated for a 20 with just 50% of the required power. Where did...
  4. Sea Rider

    Seamax Return.-

    Some updates : Have installed a Hardline hour/tach meter on engine's middle tiller handle, owner is most pleased, was driving hin nuts to manualy write down the boating hours on a log booklet. Hardline meter toggles between hour and rpm readings by pressing a small platic actuator. With engine...
  5. Sea Rider

    1992 Tohatsu M25C2 (25C2 #27906 vs 30A3 #21031 ) Carburators

    Don't worry Lukus, that's what Iboats forums are for. Instead of buying a 30A4 carb, buy an induction Hardline or Tiny Tach, you can install it on tiller arm right next to grip, good to check max wot rpm achieved under any load condition, play with prop pitches if maximizing prop to suit better...
  6. Sea Rider

    water deflecting off outboard and spraying over back sides of boat

    Never.. That lower leg has a odd shape typical of old OB's. If your engine has a sharp edge shape between WDP & AVP, raise engine with shims accordingly till water <<< flow skims right under WDP. For that to happen will need to know visually at which lower leg height is water flow passing...
  7. Sea Rider

    water over the transom

    Mike, Having a long shaft engine with rounded middle leg section water flow could splash at speed over or outer transom. Your issue is water flow is hitting at around (1) when flow (2) should be skimming right under (3) shim engine accordingly till this sweet engine/transom height is dialed in...
  8. Sea Rider

    1992 Tohatsu M25C2 (25C2 #27906 vs 30A3 #21031 ) Carburators

    You are welcome Lukus, That carb looks different than the 30A4 carb, is the shot pic still with carb attached onto manifold ? 30A4 carb has 2 bolt holes located at 3 & 9 o'clock position, your seems to be at 4 1/2 and 10 1/2 o'clock position. The butterfly portion is wider than the begining...
  9. Sea Rider

    1992 Tohatsu M25C2 (25C2 #27906 vs 30A3 #21031 ) Carburators

    Lukus, Can't tell don't work with older 25C2 OB's just with newer 30A4 ones, probably same carb, those 25 & 30 have not evolved much throughout the years, are basically same, the only difference is carb and timing restrictions being both 430 CC. Don't have right now a 30A4 at shop to check...
  10. Sea Rider

    Repitching.-

    Want to buy a mediun size alum 8.5 pitch prop but seems is no longer being fabricated, just 8-9 whole numbers. Searched through Internet and found a prop shop in Texas who can repitch 2 down, 2 up sizes from 8.5. Thought that blades had to be chopped down and welded back at a different angle of...
  11. Sea Rider

    I swear...

    Went back to my original factory delivered 9 pitch prop and removed the throttle restriction. With new trim setting engine achieved 5750 out of 5800 max wot revs with same 400 Kg while solo driving. Incredible how can an engine increment + 150 revs just by trimming right, sitting at proper...
  12. Sea Rider

    Outboard Gas Motor suggestion for my SIB

    Tango, Having made your mind already to count with that type of sib that fills all your boating requirements, must be aware of some tech flaws related to rear engine mounts : -Engine must be trimmed to sit perpendicular to mount and water level. -When engine pushes forward, front mount will...
  13. Sea Rider

    1970 15' Mirrocraft w/ Merc 50HP. Help me find my starting point for a proper prop.

    To have 3 boating issues at same time, this is what's going on at back transom : Your engine has power or manual trim ? Water flow is passing (red line ) very close to AV Plate, when should be passing skimming right under (green line) Water Deflector Plate. If you look back while at plane...
  14. Sea Rider

    Prop problem definitions

    Some clarifications to get a properly psyched thought. We're talking about small to medium size boats, say in 12- 17 ft range & manual trim. You can't achieve superb close tight turns prior matching sweet engine/transom height as prop will aerate if engine is not correctly seated. The sweet...
  15. Sea Rider

    Test Running Merc 7.5 OB muffs/barrel?

    Just to give the idea... Happy Boating
  16. Sea Rider

    Prop problem definitions

    Texasmark. Have installed engines on near flat, small, medium and deep V hulls following same exact procedure. The transom angle has nothing to do, that's what trim holes or power trim is all about, that is compensates the angle at which the engine sits on transom. Engine needs to sit...
  17. Sea Rider

    Prop problem definitions

    Your set-up has a spectacular powerful flat middke wake, same as mine running a much less HP. The difference between both set-ups is hydraulic versus manual trim. I'll bet you that if you had a manual trim and engine set at 90 deg and water flow skimming just under WDP you could make close...
  18. Sea Rider

    Prop problem definitions

    In older engines that's usually the average height between Def Plate and AV plate, newer ones can have as much as 5", are more friendly to play with different engine heights. Is that a tiller steered combo or has a central console. If tiller, pull you head over transom and have a look while...
  19. Sea Rider

    Prop problem definitions

    This is a condensed version of lower leg issues, 2 themes are involved : (1) Splash Issues (2) Lower Leg Performance. -If having water splashes out ot over transom, raise engine accordingly till water splashes disappears completely. -Depending on lower leg height cond could achieve 3...
  20. Sea Rider

    roaster tail problem (pics)

    Had same exact issue, now combo is running like a champ. Try this : Raise engine fully up using holes and go for a wot spin, back splash should disappear, lower engine a hole at a time till water flow skims right under small upper water deflector plate, that's the sweet engine/transom height...
Top