1990 170HP Merc rust in cylinders

Ok, im going to be getting a boat here within a week hopefully. It has a 170 in it, from which I gather is a 3.7 inline 4. No problem there. Here's the question, with some info. Guy said the motor needed replaced, as the mechanic left the plugs out, and the cylinders rusted. He pulled the head off to check it, and the best answer I can get so far is that it could be rebuildable. If I get this thing and the rust appears to have not caused pitting, and the motor will turn, could I just clean the rust out of the cylinders with PB or WD-40 or something, slap a new head gasket on it and go to town? Obviously, the head would be looked over since its off, and normal maintenance done to it before firing it up, ie. Oil change, etc. I may even fill the cylinders up with marvel or something for it to soak on the rings. Just didn't know if I could get away cheap here, with some gaskets, time, and fluids? Thoughts?

Re: 1990 170HP Merc rust in cylinders

Just didn't know if I could get away cheap here,

Click to expand...

That's what everybody wants, but very few receive.

You have the most problematic engine Mercruiser ever designed and you are hoping to cheap it together :facepalm:
Seen to many posts like this to know that no one will tell you what you want to hear. So will just say good luck with your project

Re: 1990 170HP Merc rust in cylinders

It has a 170 in it, from which I gather is a 3.7 inline 4. No problem there.

Click to expand...

If you haven't already "paid" for it, you might want to do a little search and do a bit io RE-search on it before you "pull the trigger".

A search here and on google/yahoo will do the job. Search for "Merc 470" , "Mercury 3.7L" etc.....


Good luck. Most here will say you're gonna need it.


Sorry about that,


Rick

Re: 1990 170HP Merc rust in cylinders

Ok, im going to be getting a boat here within a week hopefully.

Click to expand...

Ayuh,... Hopefully,... Ya didn't Pay anything for it...

For the rest of yer questions,...
Nope, she's Junk... 'n not worth investin' in...

Re: 1990 170HP Merc rust in cylinders

BamaGunner said:

It has a 170 in it, from which I gather is a 3.7 inline 4. No problem there.

Click to expand...

thats the BIGGEST problem with the boat

don't buy it, you will be glad you didn't

Re: 1990 170HP Merc rust in cylinders

There were a couple of 470 used engines on EBayMotors.com last week, and I think they wanted $900 and $1200 for them. The more expensive motor looked really nice.

Junk the old engine, and install a good used engine. Unless you've done bellows before--get a pro to align and put on all new bellows.

I too had a 470 that dropped a thrust bearing bolt into the oil pan. I had the machining done, but never got around to putting the engine back together. It had a Mercury block and crank, Ford big block pistons and bearings, and AC/Delco electrics. They were built by great machinists--custom fit every bearing. Ran strong at middle RPM's and above but was a little slow coming out of the hole--like all 4 cylinder I/O's. The 4.3 was a big improvement--great engine.

Re: 1990 170HP Merc rust in cylinders

Ok, so apparently its a bad engine...lol is there any others that drop in its place? The boat has all new interior, outdrive looks like new, as prop, and I would be getting it for around 500. I could put a little in it and still be ok, I think. Its not going to be used tons, but enough, and with a 7 month old, it will be mainly go and float, pull a tube when she gets older...

Re: 1990 170HP Merc rust in cylinders

looks can be decieving, a $500 boat is never a good deal

pass on this one, its gonna be way too much trouble for you

look for a good running boat with a 4.3 liter mercruiser package, worth the extra investment - you WILL save in the long run if you keep the boat properly maintained

Re: 1990 170HP Merc rust in cylinders

and I would be getting it for

Click to expand...

Ayuh,..... Free, is Too Much,....

Unless there's Serious commitment, 'n funds for the Project....

Re: 1990 170HP Merc rust in cylinders

You have no idea how your wife is going to, well what a "wife" does! Espeacially, with your 7 month old!

Don't do it!

Re: 1990 170HP Merc rust in cylinders

The plugs were left out of it and thats why it was rusted? More likely there was water getting into the engine, the plugs were pulled to see how/why/how much etc and the mechanic and owner, both knowing the ins and outs of this model engine, gave up and decided to ditch it.

Rusted cylinders are one thing, we havent even gotten into talking about the voodoo water pump and charging system that *will* rear their ugly heads sooner or later (probably sooner).

My 470 was very well taken care of, and I had a good 5-6 years with it, and its still a maintenance monster. And my enthusiasm for it is wearing thin. Very, very thin....

Iif the one you are looking at ran, didnt already have known issues, and was in good shape, it might be worth a shot. But the way it sits now, you dont want this boat. You dont. You really, really dont. Trust me (and the others).

Re: 1990 170HP Merc rust in cylinders

From talking to local shops the speedie sleeve repair on the water pump cam seals lasts 2-3 yrs, then you have to do it again. So if pulling an engine every 3 yrs is not a problem for you, then by all means go for it. NOTHING will bolt into the transome plate, you will have to gut the engine compartment and swap EVERYTHING over if you want another engine. The length of the 470 does not match the inline six or inline four GM engines, so you may be in way too deep.