# 26 Ultra- Rpm's Degrade in gear after 1 to 2 minutes **URL:** \ **Category:** Newsgroups Archive Prior to 2025\ **Created:** [May 31, 2025, 9:07pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933 "2025-05-31T21:07:53Z")\ **Posts on this page:** 13\ **Page:** 1
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [May 31, 2025, 9:07pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/1 "2025-05-31T21:07:53Z")
Hello, Westerbeke 21A Engine with all filters (2-fuel), fluids (transmission and engine) recently done. New impellor just done. No smoke, good exhaust water. What happens: Engine starts on first attempt. Engine purrs from 500 to 3000 rpms, can go up and down without a problem. Temperature gauge reads about 140. Once shift is in forward, the boat advances. Within 1 or 2 minutes, the rpms creep down from 2000 toward 1000 and below with no throttle adjustments. Increasing the throttle has minimal to effect. The engine will conk out it I didn’t put throttle in neutral and restore rpms to 1500 to 2000. Once rpms are restored, I drop rpms down and I can put it in gear again. It will limp along at 2000 rpms, seeming to make an effort, wanting to stall out, and increased throttle has no effect. Thanks in advance. Any thoughts? Richard Templeton Swell #230 26 Ultra Annapolis ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [May 31, 2025, 9:17pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/2 "2025-05-31T21:17:41Z")
Richard, Exact symptoms I had when heavy weed wrapped around prop near Stonington CT. Don Ringsmuth Selkie 30U 425 Traverse City, MI ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [May 31, 2025, 9:25pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/3 "2025-05-31T21:25:27Z")
I had somewhat similar problem with propeller covered in barnacles before having boat lifted for spring cleaning. Couldn’t get above 1500 rpm. Second choice would be your fuel pump is failing. > **(attachments)** > > ![PXL_20210621_183820133.jpg](https://cdck-file-uploads-canada1.s3.dualstack.ca-central-1.amazonaws.com/flex011/uploads/n26_115_233/original/1X/ef9679fed623eeec64c15c745cef129b2d1b32ab.jpeg) ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [May 31, 2025, 9:36pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/4 "2025-05-31T21:36:34Z")
140 seems a low temperature. Is that the max it gets to? If not, what is it when acting up? Have you checked for something around the prop/shaft? ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [May 31, 2025, 9:47pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/5 "2025-05-31T21:47:54Z")
I vote for the fuel pump. That happened to me on my Tartan universal 50. I had decided the electric fuel pump was just window dressing. SO I just turned it off. Most of the time it seemed to run OK AND Then it didn’t. Fran Cichowski NS 30C #300 Spicers, Noank, CT [captfran1@gmail.com](mailto:captfran1@gmail.com) ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [May 31, 2025, 11:05pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/6 "2025-05-31T23:05:23Z")
Hi Richard, we’ve had a similar issue and it turned out to be a very dirty filter in the Racor water separator. The engine would run for 1/2 hour or so and then the revs would die. After a short period at idle the fuel pump was able to push some fuel through the dirty filter but not enough for continuous operation. Once that filter was changed all went back to normal. An easy way to determine if this is the issue is to just remove the filter in the Racor unit and try the engine again. The other filters on the engine will suffice for this test. Another possibility is that there’s a screen on your fuel pick up hose and this may be blocked. Good luck…Ron Ron & Diane Schryver “Alpha Waves” 1987 NS30U #393 Georgian Bay Midland ON ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [June 2, 2025, 3:32pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/7 "2025-06-02T15:32:06Z")
Don, Don, Brian, Frances, Jim and Ron! Thanks for all the input! I am pulling boat to paint the bottom and will inspect prop, and will check on all the other suggestions. Will tether test the boat in the slip, and maybe get a mechanic involved. Richard ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [June 2, 2025, 4:49pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/8 "2025-06-02T16:49:16Z")
Richard - As per Jim Cosgrove’s theory, also check the fuel vent itself on the hull. The screens get corroded and clogged by the corrosion, which can also cause the vacuum pressure preventing fuel flow. Bob Gehrman NS30U #396 “Quickbeam” Baltimore, Maryland ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [June 2, 2025, 5:58pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/9 "2025-06-02T17:58:30Z")
I’m prone to open the vent hose somewhere and run the engine. Also, if the screen is still on the pickup tube, that could cause it. Joe Valinoti S/V iL Gatto NS30U #221 Sea Harbour YC Oriental, NC USA ```auto ``` ---
**Author:** ![user40](https://avatars.discourse-cdn.com/v4/letter/u/c67d28/32.png) [@user40](https://nonsuch.discourse.group/u/user40)\ **Post date:** [June 3, 2025, 12:05am UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/10 "2025-06-03T00:05:48Z")
When it starts to loose power open the filler cap. If it recovers it is a tank vent problem. If not I would check the screen in the bottom of the lift pump. They made paper strainers for a little while till they found they would collapse and cut off fuel supply under suction. Peter Farley Knot in a hurry 30 u #328 Keyport nj ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [June 4, 2025, 3:41pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/11 "2025-06-04T15:41:58Z")
Sounds like fuel starvation. Air in the lines would cause it not to run at all. As mentioned the vent, filters and pick up tube are the easy things to check. In that order The pick up could be obstructed with debris. Mine was too close to the bottom and needed to be shorted to 1/2 inch off the bottom. I had a vent obstructed by spiders, removing the fuel fill proved that was the cause. Is the lift pump ticking? That would be the next item. If this does not solve the issue then it is possible you have a small air leak. Any presence of fuel at a connector is a sign you need a strong light to detect these leaks. One trick to locate the source is start the engine to idle and in order, use electric tape to seal each connection increasing the throttle each time… if the the engine stalls tape the next one… when the stall stops happening you have your leak. If you changed the 2 filters on the engine you will need to tape test those connections as well. Electrical tape works There is a small chance it is the high pressure pump but that requires a mechanic skilled in dealing with these pumps. ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [June 5, 2025, 12:38pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/12 "2025-06-05T12:38:54Z")
If all else fails, it is time to check and service the injectors. John Newell Mascouche 26C 1 Toronto ---
**Author:** ![system](https://canada1.discourse-cdn.com/flex011/uploads/n26_115_233/original/1X/39e3f8ffb93f4278d654ae38d831066e407d616b.jpeg) [@system](https://nonsuch.discourse.group/u/system)\ **Post date:** [June 5, 2025, 8:27pm UTC](https://nonsuch.discourse.group/t/26-ultra-rpms-degrade-in-gear-after-1-to-2-minutes/9933/13 "2025-06-05T20:27:29Z")
Bob, Joe, Peter, Debbie, John and all previous persons. Thanks for all the input. Fuel vent and cap off make no difference. Made an in-slip tethered trial and degrading in gear is the same. It just migrates from say 3000 to the point of stalling unless put in neutral and rpms can be increased smoothly to 3000. Temperature about 160 as usual. Transmission and pro seem normal, Pulling boat week next to paint and will inspect. Will have a mechanic address the problem and take your suggestions to heart. Richard