Loud clicking at 1500 RPM + from behind starter 1985 Merc. 140MR hp engine

7/12/16 - Owned for 31 yrs, a 1985 Cheetah 166 w/Merc. 140 MR hp (181cid) & Alpha stern drive with 412 operating hours. Conducted normal maintenance over years. Recently conducted maintenance on upper and lower stern drive with new shift shaft, oil seals, bearings, water pump, u-joints & yoke shaft splines in good condition, installed new gimbal bearing & seal with recommended driver/bar, carefully checked alignment on engine coupling (splines also in good condition) and made small adjustment at front engine mount, engine tuned with new points, condenser and plugs, with dwell and timing on spec.
....Conducted first in water test with engine at spec., normal operating temperature and oil pressure, the engine & stern drive performed flawlessly as in prior years. When engine exceeded 1500 RPM, a loud metallic ticking sound emanated from left rear of the engine behind the starter at bottom flywheel bell housing & would increase 25% in loudness at 2000 RPM. Decrease engine rpm to 1500 or less & the ticking fully disappears. This ticking occurred regardless of the sterndrive's position.
....Removed sterndrive and tested engine (water fed through water intake on housing), same loud metallic ticking sound began at 1500 RPM, increase in loudness at 2000 RPM & fully cease at 1500 RPM or less.
....This metallic ticking has never occurred before. :?: Insight on this matter would be greatly appreciated.

Thanks, RBell, Virginia

 

Welcome to the forum.

Pull the starter and check the drive spring in it's nose. Also do a full "nut and bolt", which is to check the tightness and torque settings, just in case something was missed. Also look at the starter side of the flywheel for fresh metal marks and scrapes, indicating something is hitting it. Lastly, was the flywheel carefully inspected. I've seen cracks around and near the bolt holes that would let it flop around and make all kinds of racket.

 

Tue. 7/12/16 - Many tks for your insight. I will remove the starter and check the drive spring including tightness and torque settings on the starter. And, while the starter is removed I will visually inspect the flywheel through the opening for any indication of metal scrapes, etc.
...This is the original (1985), factory installed starter and to date has not given any problems. So, when writing the initial post about the loud ticking noise I was hoping that it may be the starter beginning to fail, i.e. - not disengaging, etc, and hopefully not the flywheel, which will require removal of the engine to correct/replace. The flywheel has never been inspected. I will also check for cracks in and around the bolt holes. ....Interestingly, and as noted in the initial post, there is absolutely no metallic ticking noise until engine rpm's hit 1500+.
....I will post my findings after completing this late tomorrow afternoon, Wednesday, 7/13/16.

Thanks again!
Roger
Pulaski, VA

 

Wed. 7/13/16 To: PAR - Yacht Designer/Builder ---- I partially completed the recommended procedures as follows: 1) removed the 1985 (original) Delco Remy starter, inspected starter teeth and found some wear on forward teeth that engage flywheel (rounded edge of teeth from square edge est. 3/32 inch wear) with balance of the starter teeth in good condition. No obvious metal shavings, slight amount of grease in housing has grey coloring), 2) inspected flywheel with bright light and mirror in addition to feel, noted that the edge of the flywheel teeth facing the starter is slightly burred reducing edge of teeth by estimated 3/32 inch. Thus, there is a bright metal edge to the flywheel teeth. Otherwise, the teeth are in good condition with no chipping or other signs of wear, 3) swabbed accessible interior area of flywheel housing and found little or no metal filings, 4) conducted feel and visual inspection for cracks around exterior housing or bolts and found none, accessible bolts are tight.
QUESTION: The metallic – loud clicking noise occurs at 1500 RPM and increases in loudness above that RPM, with no audible metallic clicking under 1500 RPM. If the starter bolt was not withdrawing adequately, why wouldn't the metallic clicking occur regardless of the RPM ??
…. Regarding the balance of your recommendations, please advise specifically how I should check the drive spring in the nose of the starter in addition to the tightness & torque settings on same.
…. Again many thanks for your time and insight on these matters.

Regards, Roger Bell
Pulaski, Virginia

 

The "nut and bolt" routine is a standard practice and it simply is to physically check each and every fastener. Some just need to be tight, while others are torqued. As to the RPM thing, I'm not sure, but could see a starter nose gear getting sucked into the flywheel, if the bendix mechanism is broken (spring). You can test this by pushing on the drive gear, as it spirals up the shaft. It should move smoothly and should retract fully when released. Sometimes the groove the gear rides can get a burr, which can hang the gear in the part way retracted position. Pull the starter and put a set of jumpers on it, to spin it up. Cycle it several times and see if it hangs.

It's difficult to diagnose these sort of thing this way. If it was my boat, I'd start it up and run it up to 1,600 RPM. Using a very special tool in my ear (1/2" dowel about 18" long), I'd hunt around, trying to pinpoint the noise location. Then there's the sound itself. An experienced mechanic can usually tell what it is, simply because they've heard it many times previously. Again, if it was me, I'd start thinking about what I'd just completed on the boat and focus on the area where work was preformed, that is also where the noise is coming from. You've narrowed it down to the starter area, but can the probe (stick, stethoscope, etc.) refine this a bit? Is the noise louder when on the starter, bellhousing, maybe someplace else?

 

Thursday, July 14, 2016

PAR - thanks for your prompt reply! Your comments of 7/14/16 are helpful. FYI. I removed the rear seats and engine hatch cover so I have visual and physical access to both sides and the rear of the 1985 Merc. 140MR – 181 cid engine (with Alpha stern drive). This access was of considerable help in removing the Delco-Remy starter from the engine yesterday evening.

… Regarding the "nut and bolt" routine, with a socket wrench, I checked the bolt/fastener holding the flywheel cover and found all to be tight. Also checked all bolt/fasteners on the oil pan and only found one loose (rear) bolt/fastener that was not accessible until I removed the starter late yesterday. Again, I did not find any cracks on the flywheel cover or near the bolt/fasteners.

… On the Delco-Remy starter, I noted prior that there is a bright-clean metal (not dark or rusted) slight scrap/burring ring on the edge of the flywheel's metal teeth (facing the starter). As the scraped metal area is not rusted at all, this appears to be very recent scrap/burring. Could this possibly be the starter nose gear being vibrated or pulled back into the flywheel due to vibration at higher rpms ??
… This evening, I will connect the starter to a battery and observe same as it engages & releases, and will cycle it a number of times to see if the starter engages & retracts smoothly or if it hangs.

… As to pinpointing the location of the sound, the primary maintenance was performed only on the sterndrive unit and, the gimbal bearing, gimbal oil seal replaced and engine carefully aligned. As to the engine, only the oil, oil filter, points, rotor, distributor cap (incl. dwell/timing set), and fuel pump filter were replaced on the engine.
Note: During the limited/slow test run, I placed my ear within 10 inches of the flywheel/starter area on several occasions to establish the location of the loud metallic clicking. At no time was there unusual vibration occurring in this area. Returning home, I removed the sterndrive unit and retested the engine. The same loud metallic clicking noise occurred at 1500 rpm and ceased under 1500 rpm (as it did on the limited/slow test run several hours earlier). Again, the loud clicking sound came from the area immediate to the starter and lower flywheel housing. There was no clicking/tapping emanating from the mechanical fuel pump nor from under the valve cover.

… FYI. During my limited test run to check the newly maintenanced sterndrive, the boat remained dockside as it came to normal operating temperature in neutral at idle (700 rpms) while I observed the engine and sterndrive. While in neutral, I increased rpms to 1500 and immediately heard the loud metallic clicking for the 1st time, and immediately reduced rpms below 1500, with the loud metallic clicking ceasing. Put boat in gear moving at 4 knots and conducting various slow turns, the same noise occurred again at 1500 RPM and ceased below 1500 rpm.

I will do a bench check as to the electrical function of the starter this evening and post the results on this forum late p.m. today.

Many thanks for your kind insight and assistance on this matter!

Regards, Roger Bell
Pulaski, Virginia
Purchased new in 1985 Cheetah 166 Bowrider
140MR hp Merc.& Alpha Stern Drive

 

Thursday, 7/14/16 @ 9:55 PM EDT

....Update: Bench tested starter numerous times throughout a 20 minute time frame on off with "on" times up to 10 seconds before removing power. This allowed for the unit to heat up. The starter nose gear moved up the shaft solidly and spun at a constant rate until power shut off, with starter nose gear retracting solidly. This was repeated numerous times without fail. The retaining ring remained in place as it should. The starter engaged and disengaged quickly and solidly each time.
.... I realized that the starter has no load on it as it would if engaging the flywheel gear and turning the engine over. This might make a difference since the amperage draw would likely increase if it was under load and possibly affect the disengagement of the nose gear.
.... So at this point, unless there is some other determination I can make without the starter attached to the engine, I will ...reinstall the starter and again attempt to more exactly pinpoint the "solid" metallic clicking sound with a stick or stethoscope.
....Any thoughts on this???

Kind regards,
Roger Bell
Purchased new in 1985 Cheetah 166 Bowrider
140MR hp Merc.& Alpha Stern Drive

 

The point of the stethoscope (or dowel in my case) is the isolate the noise. Your ear can't do this nearly as effectively. Once the noise is up and running, the stethoscope will tell you if it's physically in the starter, the block, where in the block, the bellhousing, etc. Once you probe around, the location will become pretty obvious. Does this starter have a forward bracket, holding up the contact end? Does the starter employ shims?

 

Fri., 7/15/16 - 10:30 am EDT
... I plan to reinstall the starter this p.m. and carefully re-ascertain the location of this loud metallic clicking using the stethoscope. As to this original 1985 Delco-Remy starter, it has three holding bolts. A forward bracket (cast part of the starter head) with a short bolt & long bolt on either side of the starter head immediately adjacent to the flywheel cover, and a small "L" rear bracket that bolts to the starter end and to the block. No shims are used.
... I will post an update later this p.m. Many kind thanks for your time and insight!

P.S. I am going to resolve this problem, ...somehow.

Best, Roger Bell
Purchased new in 1985 Cheetah 166 Bowrider
140MR hp Merc.& Alpha Stern Drive

 

Thrust bearing

This sounds like a thrust bearing problem as the torque increases the flywheel
moves out on the crankshaft and contacts starter motor

 

Monday, July 18, 2016
11:05 pm EDT

Folks, sorry for the delay in posting. I appreciate your respective thoughts on this matter.
... Note that I removed the stern drive late last week and conducted run engine tests to ascertain location of the loud (metal on metal) metallic clicking that increased in loudness and rapidity as RPM increased. The loud metallic clicking continued.
... Late last week, I removed the boat's original 1985 Delco - Remy starter and conducted a a series of extended bench tests of engage/disengaging the nose gear, which the starter did quite satisfactory. There was no handing or looseness in or at the starter's nose gear.
... Ordered new replacement starter from DB Electrical of Kingsport, Tennessee of who I have found be very reliable and forthcoming on their products. Installed new starter this evening and conducted a series of starts, operating timeframes to ensure that engine was at normal operating temperature, and ran RPMs up to 2500. Engine cranked immediately, maintained 700 RPM to allow engine to warm up to operating temperature. Increased RPMs to 1500, 2000, and 2500.
... Results: The loud metal on metal clicking did not occur at any time throughout these run engine tests. HALLELUJAH. I can only speculate as to why the original 1985 Delco-Remy starter was possibly engaging enough to slightly burr the edge of the flywheel ring gear. The vibration may have caused the nose gear to release and float to the edge of the ring gear without engaging.
... I will remount the sterndrive. Hopefully the weather will permit me to conduct a test on the lake sometime late this week.
... I will keep you informed and post the results of these tests on the lake.

Many thanks to you for your guidance on this matter.

Best, Roger Bell
Pulaski, VA
Purchased new in 1985 Cheetah 166 Bowrider
140MR hp Merc.& Alpha Stern Drive

 

Cool deal, now splash that puppy and have some fun . . .

 

Tue., 7/19/16 @ 10:am EDT

PAR ...many thanks! Will post the results of my boat's test run on the lake later this week.

Best, Roger Bell
Pulaski, VA
Purchased new in 1985 Cheetah 166 Bowrider
140MR hp Merc.& Alpha Stern Drive
Edit/Delete Message

 

Sunday, 7/24/16

Fellows, relative to the loud metal on metal clicking sound occurring on my 1985 140MR hp Merc. And Alpha stern drive, as noted prior I replaced the original 1985 Delco –Remy starter with a new one. I conducted test runs on Thursday and Friday of this week and found absolutely ....no.... re-occurrence of the heavy metal on metal clicking noise which emanated from the starter/lower flywheel area of the boat engine. Prior to these test runs, I also checked the alignment on the engine to ensure that the new gimbal bearing and engine coupling was in good order.
... Repeated several engine starts, engine started quickly each time with no complications. On 1st test run with an on-board assistant, allowed boat to warm-up to operating temperature at dockside at around 700 RPM idle. Operated boat in a series of slow left and right turns and figure eights operating at 1500, 2000, 2500 RPM while observing and listening to performance of engine and the newly maintenance stern-drive. Engine and stern-drive operated as should. Returned home and checked all fluid levels on engine and stern-drive with all in good order.
... On 2nd test run, ran boat at increased RPMs through 3000, 3500, and 4000 rpm in straight runs and wide turns including accelerating from a dead stop as used when pulling a skier. Absolutely ..no.. metal on metal loud clicking from the starter/lower flywheel area or from any other part of the engine.
... Very pleased with the performance of the boat's engine and stern-drive. I hope this forum thread will be of some help to others who face a similar perplexing problem. Your insight and support provided me the impetus to pursue this problem until it was resolved.

P.S. Had a most enjoyable evening on the lake with friends and was nice to know all was well with my boat's mechanical performance!! First time on the lake this year.

Many thanks to PAR!

Warm regards,
Roger Bell
Pulaski, VA
(Purchased new in 1985 Cheetah 166 Bowrider
140MR hp Merc.& Alpha Stern Drive)