• If this is your first visit to the iboats.com Boating Forums, be sure to check out the FAQ. To post a question or comment, begin by signing up. To start viewing messages, select the forum that you want to visit from the selection below.
  • ALL iboats Forum Members and Guests:
    To show our appreciation for your participation in the Forums, we're offering an exclusive Forums-only discount good for an additional 5% off your iboats.com order for a limited time.
    To redeem, simply call our Customer Service Team at 800-914-1123 (Open M-F, 9am - 8pm Eastern Time) and mention the Forums 5% off discount. Offer excludes engines, trolling motors, and electronics.


Announcement Module

Help Tip: If you have a question that has not been answered to your satisfaction in the archives, it is always best to start a new thread of your own. By starting your own thread, you will receive the maximum number of views by forum members.

Below are some additional forum policies in hopes of all iboats members will follow, Thank you.

1. Please do not reply to old threads or hijack existing threads. Old threads of a technical nature are like a library book, Please do not write in them.

2. Old threads should be considered archives and used for reference only. Please do not reply to them.

3. Do not take over someone elseís thread (aka hijack) with your own question, even if it is similar. If you have a question that has not been covered to your satisfaction in the archives, it is always best to start a new thread of your own.

4. If you have a question for the original poster (OP) and the thread is over 30 days old, send the OP a PM, he may not even visit the forums any longer, or may not notice your question in the old thread.

5. By starting your own thread, you will receive the maximum number of views by forum helpers that may not even notice your question when itís posted at the end of someone elseís thread. And those answers will be specific to your particular issue.

6. Please do not post to threads that have been inactive for more than 3 months unless you are the original poster. We have very active forums and any thread that remains inactive for that long should be considered "dead". It is especially confusing when there is an entirely new question posted to an old thread.

7. Posting at the end of any thread is considered to be hijacking the original posters thread which in turn subjects the thread to be closed if it continues to happen thus not making it fair to the original poster in the future had for some reason he/she needed to return for additional information or provide an update of the problem solved which is always welcomed within a reasonable amount of time frame.

8. Please note that you should see a red banner pop up near the bottom of each inactive thread asking you not to reply to old threads. The Red banner will read: Please note this thread has been inactive for 90 days. For the best results, please start a new thread.

Thank you all in advance for doing your part in helping iboats run a smooth ship.

Additional forum rules linked below.
See more
See less

Engine RPM seems to be pulsing

Page Title Module
Move Remove Collapse
Conversation Detail Module
  • Filter
  • Time
  • Show
Clear All
new posts

  • Engine RPM seems to be pulsing

    Hi all,Got a strange one thats been happening for the last month or so. It a Honda 40, Tiller. Between 1000 and 3000rpm, doesn't matter where, If I hold the throttle at any given position, I'm getting a slight pulse in the RPM, Kind of at the rate of "one-and-and-two-and-three-and...". RPM's according to the tach seem to be holding steady, but theres a definite fluctuation going on. Hit the throttle and the acceleration is instantaneous so it must be something minor. Usually it doesn't happen at idle, only when I'm at no-wake speeds.Could I be getting a carb out of synch? I've ruled out the obvious. I've put on a brand new prop, the prop shaft is not bent. Primer buld is hard, not a fuel delivery problem. Gas tank is vented. Other that this, the engine runs smooth as ever.Anyone ever had this type of experience?Nav

  • #2
    Re: Engine RPM seems to be pulsing

    Have you tried adjusting the idle mixture? It sounds like the mixture may be a little off. Can't tell from your description whether its too lean or too rich. Run the engine at the rpm that causes the problem and then kill the engine and pull the plugs. The plugs may give you some insight as to which way to go with the mixture. My first guess would be that they are lean.