Engine cranks but will not start

[Rick Stephens]

I would suggest that buying any older boat, and 25 years old is older, you should expect to need to service the bellows, u-joints, gimbal and any other wear item. You may not need to do all of them, just expect they need replacement when you buy an older boat.

There are TONS of how to videos on maintenance of Alpha 1 Gen2 drives. achris, who posted above, has a link to many of them at the bottom of his post. His are probably the best, most accurate of any. You have no idea how many hours and $$ he saved me when I first got into servicing my own 25 year old Mercruiser.

I have one other item of possible approach to your problem. You should read up about shift interrupt systems in the Adults Only section. That thread has more information that you need to know than anywhere else, period. It is essential reading. Knowing how the shift interrupt works, and why, will help you to diagnose if it might be your problem. From your description, you seem to often be able to get the boat working on land, then it stops once you are on the water. It may be a faulty switch or adjustment is causing you an intermittent issue. Don't hang your hat on it, but is worth the effort to read up on the shift interrupt so you can rule it out.

Rick

 

[kulle]

Thanks Rick...and yeah I expect the have to service or give more TLC to this boat, just didnt think I would have needed to 1 month after getting it ( bought mid may, ran once great, then issues) given the seller seemed to be sincere in how he maintained the boat, etc. I actually disconnected the shift interrupt switch the last time i was out to rule it out 100% and it made no difference, still shut off. But now i have to deal with a torn bellow, so I cant even get on the water to test the changes I made. I was told there is a way to replace the main bellow without having to remove the whole outdrive, basically unhinge the union and slide off bellow, slide new on on , reconnect union- I know i should be removing it all to inspect.

 

[nola mike]

Don't even consider doing this without removing the outdrive. You need to inspect the u-joints and gimbal bearing (and you should check the alignment when you're in there). Removing the drive is literally a 5 minute affair. If you don't want a boat that breaks, a) don't buy a 25 year old boat, and b) don't buy a boat.

 

[kulle]

I'm pretty mechanically inclined....I'm sure I can remove it with all the videos. 5 mins !? Sounds like you;ve done it a few times. Just trying to decide whether i want to risk messing anything else up or leave it as is, winterize it and look to trade it next season.

 

[kulle]

That too.

Chris I watched your video on removing the Alpha gen 2 drive ( i'm going to attempt the bellow replacement). In your video I heard you make brief mention about an oil vent at the top of the drive. Did you say you have to remove it on the gen 2 drives ? If so, remove like loosen or totally remove? Thanks and great videos...i've seen them before i joined iboats !

 

[Bondo]

I'm pretty mechanically inclined....

Ayuh,..... On a 10 scale, 'n changin' the oil in a lawn mower is a 1, then pullin' the drive is a 2,.....

5 minutes is no exaggeration,....

 

[kulle]

ok i looked at it more and it does look ok of a job. Now, will just removing this gain me access to most of the parts i need to replace, bellows , inspect u joints, etc? If i wanted to install new trim/sender switches i need to remove the bell housing, using that hing pin socket?

 

[Bondo]

using that hing pin socket?

Ayuh,..... I use a 1/2" drive, 1/2" allen key socket, myself,.....

 

[kulle]

thank you sir

 

[achris]

... I was told there is a way to replace the main bellow without having to remove the whole outdrive, basically unhinge the union and slide off bellow, slide new on on , reconnect union...

You were told BS. It is IMPOSSIBLE to replace the bellows without removing the drive. The design of the bellows precludes it.

The quickest and easiest way to do any job is to do it the right way, first time. Get the Merc service manual, read through the process a few times to familiarize yourself with it, and just begin.

Chris......

 

[kulle]

The quickest and easiest way to do any job is to do it the right way, first time. Get the Merc service manual, read through the process a few times to familiarize yourself with it, and just begin.

Chris......

Are the online manuals no longer avail?

 

[achris]

Are the online manuals no longer avail?

Looks that way.

 

[nola mike]

Perhaps some kind soul with your engine might be able to help you out with a manual...

 

[kulle]

So I went through the TB IV ignition troubleshooting flowchart again. I'm attaching a pic of what I did, in the event i missed something. Basically I have the +12 at all initial locations, so the real test started with checking for spark....

My result was i saw NO spark, which the guide indicates a faulty ignition module, the expensive part. How likely could this truly be the problem...the boat starts many times , but when it just shuts off in the water, there have been times it HAS NOT started immediately...appreciate the expertise....

 

[Maclin]

It may be the make-break that will cause the coil to fire. Strike it to the ground like a telegraph key several times if you did not.

 

[kulle]

yeah thats what I did. and didnt see anything in the inline spark tester, not even a faint light. I tapped it real fast onto a known good ground bolt on the engine block. I just didnt know if that test is basically intended for people who do not have any spark to begin with.

 

[achris]

.... In your video I heard you make brief mention about an oil vent at the top of the drive. Did you say you have to remove it on the gen 2 drives ? ...

No, I mentioned that the earlier drives MAY have an oil monitor bottle that connects to the vent hole. IF your drive has that, and Gen IIs do not, you remove it...

Chris.........

 

[achris]

yeah thats what I did. and didnt see anything in the inline spark tester, not even a faint light. I tapped it real fast onto a known good ground bolt on the engine block. I just didnt know if that test is basically intended for people who do not have any spark to begin with.

Have you read....

http://forums.iboats.com/forum/engi...-mercruiser-thunderbolt-ignition-systems-work

Chris.........

 

[kulle]

Have you read....

http://forums.iboats.com/forum/engi...-mercruiser-thunderbolt-ignition-systems-work

Chris.........

NUMEROUS times. I went through the whole troubleshooting flow chart. So I guess my ignition module is faulty only when under load out on the lake.... See my comments from the testing flowchart...

 

[achris]

You're looking for a no spark condition, yet I see in that chart you have spark at times. You only don't have spark when you take the green/white off the sensor and tap it on the ground. I don't see a problem if you have spark at all other times. What am I missing?