Need HELP PLEASE! Mercury 90hp-won't crank

[cusack]

Hi,

I am completely new to this forum and also just purchased my first boat. I bought a 1987 Starcraft bass boat the other day with a 90 HP Mercury Oil Injected and I believe the engine is either an 88 or 89 model.

Ok so here is the story. When I bought the boat, the engine would not crank and yes I bought it for very cheap and decided to take my chances that I could possibly get it running inexpensively.

The previous owner said that he had last used it 6 months ago and it ran fine but all the sudden wouldn't start now. He said he had taken the spark plugs out and they were wet with gas.

I got home with the boat, changed all 3 spark plugs, added 5 gallons of fresh gas to it and the engine cranked right up to my surprise! However, it would not stay running longer than a few minutes without cutting off but would crank back up and do this every time.

Today I decided to change the fuel filter, sprayed out the carburettors with cleaner, added a quart of two cycle oil, and also added "Sea Foam" to the gas and now I've tried for the last 30 minutes and I can't get it to crank up again.

I'm far from a boat mechanic so any help that could be provided and save me some money before having to take it to the shop would be helpful. Any suggestions on what would be causing this? What should I try to do next?

Thanks

 

[MadProps]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

Id say you would do well to overhaul the carbs


pull your plugs again to see if they are wet and no longer sparking, while they are out check them for spark, insert the plugs in their rubber boot, short the plug against the block and crank it over , looking for a strong spark

if they are not wet, squirt fuel in throats of the carbs, and attempt to fire it again, if it fires...tear down the carbs....I would do the carbs regardless

 

[cusack]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

Thanks for your reply. I took the plugs back out and they are dry. I dumped some gas in all three carbs and tried repeatedly to crank it but it still will not crank. I even sprayed starting fluid into the carbs and nothing.

The only thing left is that I have not checked is if it's actually sparking which I will do tomorrow and post an update. I'm really not wanting to take this thing to this shop unless I have to and can do minor repairs/troubleshooting if someone gives me an idea on what else to check. Any other ideas besides rebuilding the carbs?

 

[Chris1956]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

If the motor did not fire when you used the starting fluid, you have no spark. Get on the CDI.com website and find the ignition troubleshooting procedure for that ADI ignition system.

In the future, use 50::1 gas/oil mix instead of the starting fluid.

 

[Silvertip]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

Do you have any "little helpers" (as in children) that may have crawled into the boat and pulled the kill switch lanyard thus killing the ignition. And please stop using starting fluid. You engine is a two stroke that requires oil in the fuel for lubrication. Starting fluid has no lubrication in it and will wash off the cylinder walls and possibly score them and/or the pistons. Use only a fuel/oil mix when spraying stuff into the carbs. I agree that you need to do a spark check first. Are you pushing in on the key (choke/prime) while cranking? Do you have the fast idle lever raised when attempting to start the engine? Are you squeezing the primer bulb to get fuel to the carbs? Many starting problems are operator error rather than equipment issues.

 

[cusack]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

Here's the latest. I took the plugs out this morning to check for spark. This wasn't easy to do by myself but I managed. Anyways, the top 2 plugs was firing fine but on the bottom cylinder I only saw it spark once although it was hard to try to hold it while reaching for the key, I even tried to duct tape it to the side of the starter but this was difficult. I'm sure I only saw it spark once after about 10 tries though.

What was weird is with that bottom plug out, it actually tried to crank better than when the plug was in there.

I finally got tired of messing with it and just went ahead and took it to the boat shop. I'm hoping it's nothing major or expensive to fix but will post an update when I hear back from the mechanic.

 

[hkeiner]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

A remote start switch and spark tester can make checking the spark a lot easier for a single person. These can be obtained at most auto parts stores for pretty cheap.

You might get lucky and not have a large shop bill this time but in the long run, an OEM shop manual, a systematic troubleshooting approach, a little patience, and this forum's excellent assistance will let you solve almost any problem with your motor at a much lower cost. It has worked for me.

 

[cusack]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

I have also posted this on a new thread but wanted to post it here as well.
The boat shop called me and said it's the switchbox that is not firing on the bottom cylinder. He says that it's $215 for that box. Then he says that it has old milky looking gas in the engine so it needs to be drained and that the carbs need to be rebuilt. All together it's $600 to fix all of this.

So I asked him if we know of anything else it needs and he tells me that you can't turn the steering wheel at all so that if he couldn't get that free-ed up then it would be another $300. UGH!

I just bought this boat and know absolutely nothing about it other than the bilge pump isn't working, I don't know if it's just not hooked up or what because I haven't looked at it yet. The seats have rips in it. The trolling motor needs a new battery.

He did say that the engine has good compression but I don't know what to do! I'm afraid to put $600 into this boat (without steering cable)and there be all kinds of other problems. The boat is a 1987 Stracraft 15 ft and I can post pictures if necessary. Should I invest $600 into this boat??? Any suggestions or advice please. This is my first boat and I have no clue what to do!

Here is a picture of the boat:
http://i4.ebayimg.com/02/i/001/15/c7/44a6_1.JPG

 

[cusack]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

I'm really not getting any replies here although I realize this has to be my decision but I just don't know what to do. I was thinking about this but how hard would it be for me to change the switchbox, rebuild the carbs and possibly fix or repair the steering cable myself? I'm usually good with working on cars but boats is completely new to me.

What would be the toughest job to repair of everything listed above?

 

[hkeiner]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

The boat shop called me and said it's the switchbox that is not firing on the bottom cylinder. He says that it's $215 for that box.

It would be cheaper to buy a switchbox online from CDI and install it yourself. There is not much to it, but you do have to avoid mixing up the wiring.

and that the carbs need to be rebuilt

Buying a carb rebuild kit and a gallon can of carb cleaner, and then doing the work yourself would be a lot cheaper than having someone else do it for you. An OEM shop manual would provide sufficent instructions on how to do it.

Should I invest $600 into this boat??? Any suggestions or advice please. This is my first boat and I have no clue what to do!

In my opinion, buying an old boat and motor and then going to a shop for most repair and maintainenace work can be very costly and is likely not a good idea. Buying an old boat and motor can be a good idea if you are a do-it-yourself kind of guy and have the basic tools to troubleshoot, maintain, and repair the motor yourself. Just my thoughts....

You definately need an OEM shop manual anyway or you are flying blind.

 

[Capt. Cooper]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

If the motor did not fire when you used the starting fluid, you have no spark. Get on the CDI.com website and find the ignition troubleshooting procedure for that ADI ignition system.

In the future, use 50::1 gas/oil mix instead of the starting fluid.

Chris1956-

What is the CDI.com site you mentioned. CDI.com is Computational Diagnostics Incorporated - The Experts In Neurophysiological Monitoring.

Mahalo!

 

[hkeiner]

Re: Need HELP PLEASE! Mercury 90hp-won't crank

http://cdielectronics.com/