3.0 Mercruiser / Alpha One - starter fires, won't turn over - 1990 Larson 170

[z0lt3c]

Hi Guys-
First post, actually, first time boat owner. I've worked on cars for many years and thought it was finally time to buy a cheap boat to abuse on NJ rivers and NY lakes rather then beg and borrow to accompany others.

I picked up a 1990 Larson 170 "All-American" from river rat type in PA and recently hauled it up to my lake home near Keuka lake in UPNY. Being a relative novice to boat maintenance and repair, and since this is cleary a used but fully functional boat (went for a long test drive before buying), I decided to drop it of at my local larson dealer, Morgan Marine.

2 weeks and $700 later I get the boat back from Morgan w/ excellent review "runs great" the say, "performed well at all speeds" is notated in the lake test results. In the end, they did full outdrive service, engine oil/fulter, fixed bad ground on blower, replaced battery terminals and installed an auto-bilge. "Doesn't need anything else" I was told.


I pick the boat up today, I ask them to leave it in the water so I can just drive it to my mooring dock, about 45 minutes away via lake @ 35 mph. They have it waiting in a slip, I start it up, cruise around for 15 minutes, no problems, get some fuel, cruise around again, and then decide to take off on the trip, since no problem and 3 stop/starts OK.

The boat makes the 45 minute trip in stellar fashion. WOT reaches around 4200 rpm, boat gets up to 40mph, no problem w/ minor trim adjustments on plane.

So 45 minutes of continous operation later, I reach my mooring dock location. As I approach the dock at very low speeds the boat begins to stall in both F and R. Had no problem like this before the trip. Dont think too much of it, go get some lunch and supplies, 90 minutes later come back to boat for 2nd run.

This time the boat won't start at all. I can hear the starter firing, I get full gauge response, boat is in neutral, fuel is good and fresh. Engine cranks and tries to start but just wont turn over. Had no problems before my long run!

Any suggestions??? Please excuse the long post. I am thinking weak batteries/bad alt, not enough CCA to turn over... but maybe boat doesn't work like car. Any other type of problem (switch, fuel, compression, timing, spark) u think marina would have found or would be present before long run.

What could have gone wrong during my run to prevent restart!!


Thanks!!

Z

 

[fat fanny]

Re: 3.0 Mercruiser / Alpha One - starter fires, won't turn over - 1990 Larson 170

Z welcome aboard
Do you mean the engine it's self will not rotate? but will not start? if so
1st off go to the top of this forum and read all selections in the adults only section (stckies). I would advise not to run the starter to long @any time they do tend to heat up also down load the manual for your engine and outdrive there free and the best deal you'll find anywhere to self educate on the operation of you power plant. After that I would ensure 2 things make sure your getting fuel and spark afetr that check to ensure your kill switch (lanyard) isn't partially in the off position make sure all grounds and wire connections are tight and not corroded. Most of the above listed items are just basics but start with that and the rest of the gang will chime in with items I missed for sure.

 

[Don S]

Re: 3.0 Mercruiser / Alpha One - starter fires, won't turn over - 1990 Larson 170

As I approach the dock at very low speeds the boat begins to stall in both F and R.

Are you saying the engine would die when you shift to F or R? If so, you may have a bad lower shift cable which will keep the shift interrup system engaged. This shorts the distributor to ground for a split second to allow the drive to shift. With a defective cable, the shift interrupt system is activated and will not release.

 

[z0lt3c]

Re: 3.0 Mercruiser / Alpha One - starter fires, won't turn over - 1990 Larson 170

Thanks for the responses!

Do you mean the engine it's self will not rotate?
but will not start? if so

I'm pretty sure the engine rotates. When I turn the inigition swtich, the starter engages and the engine belt starts to spin and the crankshaft begins to rotate, it just doesn't quite "turn-over" to get fully started.

Are you saying the engine would die when you shift to F or R?

Yes, as I was approaching the doc at very low RPM in F, and would swtich to very low RPM R, it would stall. Same thing if I tried going from very low RPM F to very low RPM R. However, no problems w/ low rpm operation before my 45 minute trip.

If so, you may have a bad lower shift cable which will keep the shift interrup system engaged. This shorts the distributor to ground for a split second to allow the drive to shift. With a defective cable, the shift interrupt system is activated and will not release.

I didn't bring any of my tools with me yesterday, thinking the marina did their job well... but today I will bring my tools down to the boat and start tinkering. It sounds like the "bad lower shift cable" maybe a good fit since it matches the symptoms well.

Is their a way to diagnose the lower shift cable with the boat in the water?

Thanks,
Z

 

[z0lt3c]

Re: 3.0 Mercruiser / Alpha One - starter fires, won't turn over - 1990 Larson 170

After understanding how to use the throttle button on the remote to put the engine in neutral w/ throttle control, I got the boat to start up this AM, first try. However, I still am having stalling problems shifting from F to R and R to F. After stalling out two or three times, I am back to be unable to start/get the engine to turn over.

So, another day of pushing off dock at idle, trying to R then F to get out, only to stall at some point and have to get pulled back in (getting pulled back in has been quite humerous to the rest of the marina).

Took apart the flame arrester and it was absolutely filled with gunk. Gave it a nice soapy water bath and it looks like new.

Inside of carb was clean, I could smell and see fuel when putting remote into neutral idle position. Exterior of carb was all gunked up (where the levers are) so i de-greased and wiped down. Left carb open to outside for a little while to let fuel escape.

I don't know if either of these things actually did anything, but after putting them back together, 15 minutes later I was able to start up the engine, after giving it a little gas it idled fine, around 700 rpm. I was able to stop start it 2 or 3 times after that with no problem.

After restarting for the 4th time, i re-secured dock lines and tried to apply power. What I noticed, when moving the remote out of neutral but before the propeller engaged in either direction, was alot of play, more then i really expected (maybe 1/4 of dead-play in each half circle direction). While the remote was in this dead position between neutral and F/R, I heard some kind of continous clicking or grinding noise coming from outdrive area.

However, after I found the point of engagement in both F and R I was finally able to apply a bit of power, switch to neutral, and apply a bit of power in the other direction. Everything seems OK.

Still sound like shift cable problem? Is the dead play and noise during normal? I am thinking I should drive it right to a trailer if I can actually get out of dock tomorrow.

Thanks,
Z