Year? 100 hp mercury? motor

Rsjs

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Joined
Apr 12, 2017
Messages
8
Hi. As I'm sure you're already aware, I know next to nothing about repairing boat engines and I am a first time owner of a boat. Just want to start off by thanking everyone for any assistance they can provide.

Ok, so at the end of last season, I bought a 24' pontoon boat with a 4 stroke 100 hp sea ray motor. It ran fine (as far as I could tell), we used it probably about 20 times in the month we had left before the docks came out of the water. The previous owner let us know that there was a problem with the trim pump, so I know I have that to repair. So I have a few questions related to the motor:

1. How can I identify the motor? From some limited google searches, I believe it is a '88-'89 mercury 100 hp. I tried pulling off the casing and I do not see any model numbers of any kind. Id like to get a manual so I have some idea of what I am doing.

2. How difficult is replacing a trim pump?

3. How much can I expect parts to be?

4. Are the parts difficult to find? Any go-to places that people tend to recommend?

5. Could I expect this model motor to have an alternator?

6. How fast should I expect a battery to drain when all that is being used are a few lights for nighttime boating?

7. We ended up charging a battery each time we went out after the first problem with the motor, but it seems like the battery would die after a few trips, is that normal?

8. When we went to winterize the engine, I found out that the air box was missing. It seems some people do this intentionally, should I look into buying one?


I'm sure I have other questions but I can't think of any others right now. I'm mostly concerned about getting the manual and starting to look for the replacement parts. If I can't do it myself, I'd like to know early so that I can either bug my cousin or bring it to the shop early before the docks go in.

Thanks again.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
36,298
Sea Ray was a Mercury motor with a white paint job.----------And are you sure it is a 4 stroke motor ??-------4 cylinder confused with 4 stroke ?-----Serial number should go along with your questions.
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
Since you obviously have opened the cowl, you said there is no air silencer, is there an oil tank visible?
 

Rsjs

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Apr 12, 2017
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8
So I was under the impression that I would be able to download a free manual pdf online, but that doesn't seem to be the case (unless one of you know where i can download a copy). I wanted to look at the manual to assess if this is within my means. Before I get balls deep into this, am I going to need any special tools to replace the tilt pump / alternator? Does this involve removing the motor from the boat?How much would a shop charge to have this done?
 

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
12,961
Well it would be better to find the source of the drain before replacing parts. The batteries themselves could have a small internal short
 

Rsjs

Cadet
Joined
Apr 12, 2017
Messages
8
I'm probably going to let that slide until I have more time, but the trim pump/motor looks like something I can do.

I saw online that you can either buy the the motor by itself or packaged with the pump. I'm almost positive the seller told me the issue is the the trim pump. How can you tell if the motor is fine?

I'm going to end up buying the manual and doing this myself. I'm sure I'm not going to get any long winded answers, but any tips/suggestions would be appreciated.
 

flyingscott

Fleet Admiral
Joined
Apr 8, 2014
Messages
7,990
What is the trim doing that you think it needs a pump? You also need to replace the air box people are under the assumption that taking it off will make the motor will make more power. That is not true at all the carbs are jetted to have the airbox in place without it it can run lean.
 

Rsjs

Cadet
Joined
Apr 12, 2017
Messages
8
Yeah I assumed that not having the air box/silencer isn't a great idea, but I saw a few posts where some people seemed to be doing it on purpose, at the expense of having a louder engine.

The trim doesn't work at all. As far as I can remember, it doesn't move or make any noise.

Going to wake her up from hibernation tomorrow and find out if I winterized it properly if you think there's anything I should check.
 
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